Search for "condensations" in Full Text gives 92 result(s) in Beilstein Journal of Organic Chemistry.
Beilstein J. Org. Chem. 2017, 13, 65–75, doi:10.3762/bjoc.13.9
Graphical Abstract
Figure 1: Typical pilot scale single screw extruder (left) and a laboratory scale twin screw extruder (right)....
Figure 2: PTFE screw employed in single screw extrusion, with increasing root diameter (RD) from 45 mm to 95 ...
Figure 3: Modulated stainless steel intermeshing co-rotating screws employed typically in twin screw extrusio...
Scheme 1: Polymerisation of styrene using s-BuLi as an initiator.
Scheme 2: Telescoping process of the formation of polystyrene, followed by post polymerisation functionalisat...
Scheme 3: Proposed mechanism for the branching of polylactide. Adapted from [23].
Scheme 4: Chemical reaction between isocyanate and an alcohol to form polyurethane.
Figure 4: Representative diagram explaining the process involved in step growth polymerisation, which involve...
Scheme 5: Generic polycondensation reaction to produce polyamides.
Figure 5: Comparison of choline chloride/D-fructose DES prepared via twin screw extrusion (left) and conventi...
Scheme 6: Synthesis of HKUST-1, ZIF-8 and Al(fumarate)OH by twin screw extrusion. Adapted from [2].
Figure 6: Synthesis of Ni(NCS)2(PPh3)2 and [Ni(salen)] by twin screw extrusion. Adapted from [2].
Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236
Graphical Abstract
Figure 1: Possible two-component couplings for various monocyclic rings frequently encountered in organic mol...
Figure 2: Possible three-component couplings for various monocyclic rings frequently encountered in organic m...
Figure 3: Possible four-component couplings for various monocyclic rings frequently encountered in organic mo...
Figure 4: Permutations of two-component coupling patterns for synthesizing the cyclohexanone ring. Synthesis ...
Figure 5: Permutations of two-component coupling patterns for synthesizing the cyclohexanone ring overlayed w...
Scheme 1: Conjectured syntheses of cyclohexanone via [5 + 1] strategies.
Scheme 2: Conjectured syntheses of cyclohexanone via [4 + 2] strategies.
Scheme 3: Conjectured syntheses of cyclohexanone via [3 + 3] strategies.
Figure 6: Permutations of three-component coupling patterns for synthesizing the cyclohexanone ring. Synthesi...
Figure 7: Permutations of three-component coupling patterns for synthesizing the pyrazole ring via [2 + 2 + 1...
Scheme 4: Literature method for constructing the pyrazole ring via the A4 [2 + 2 + 1] strategy.
Scheme 5: Literature methods for constructing the pyrazole ring via the A5 [2 + 2 + 1] strategy.
Scheme 6: Literature methods for constructing the pyrazole ring via the A1 [2 + 2 + 1] strategy.
Scheme 7: Literature methods for constructing the pyrazole ring via the B4 [3 + 1 + 1] strategy.
Figure 8: Intrinsic green performance of documented pyrazole syntheses according to [2 + 2 + 1] and [3 + 1 + ...
Scheme 8: Conjectured reactions for constructing the pyrazole ring via the A2 and A3 [2 + 2 + 1] strategies.
Scheme 9: Conjectured reactions for constructing the pyrazole ring via the B1, B2, B3, and B4 [3 + 1 + 1] str...
Figure 9: Permutations of three-component coupling patterns for synthesizing the Biginelli ring adduct. Synth...
Scheme 10: Reported syntheses of the Biginelli adduct via the traditional [3 + 2 + 1] mapping strategy.
Scheme 11: Reported syntheses of the Biginelli adduct via new [3 + 2 + 1] mapping strategies.
Scheme 12: Reported syntheses of the Biginelli adduct via a new [2 + 2 + 1 + 1] mapping strategy.
Scheme 13: Conjectured syntheses of the Biginelli adduct via new [2 + 2 + 2] mapping strategies.
Scheme 14: Conjectured syntheses of the Biginelli adduct via new [3 + 2 + 1] mapping strategies.
Figure 10: Intrinsic green performance of documented Biginelli adduct syntheses according to [3 + 2 + 1] three...
Figure 11: Intrinsic green performance of newly conjectured Biginelli adduct syntheses according to [4 + 1 + 1...
Beilstein J. Org. Chem. 2016, 12, 2343–2350, doi:10.3762/bjoc.12.227
Graphical Abstract
Figure 1: Stereoisomeric inositols.
Scheme 1: Retrosynthetic approach to inositols from aldohexos-5-uloses.
Figure 2: Hypothesis of the preferred transition state.
Figure 3: Stereoselective reduction of inosose intermediate.
Scheme 2: Intramolecular cyclization of an orthogonally protected L-lyxo-aldohexos-5-ulose derivative.
Beilstein J. Org. Chem. 2016, 12, 1788–1797, doi:10.3762/bjoc.12.169
Graphical Abstract
Scheme 1: Synthetic route to compounds 1–4 with BDT core. Reagents and conditions: i) [Pd2(dba)3]·CHCl3, HP(t-...
Figure 1: UV−vis absorption spectra of COOP-nHT-TBDTs 1–4 (a) in chloroform solution (5.0 × 10−5 mol·L-1) and...
Figure 2: (a) Cyclic voltammograms of 1–4 measured in CH2Cl2 solution (1.0 × 10−3 mol·L−1) with 0.1 mol·L−1 Bu...
Figure 3: (a) J–V curves of the best COOP-nHT-TBDT:PC61BM solar cells; (b) EQE spectra of the corresponding c...
Figure 4: AFM height images of COOP-nHT-TBDT:PC61BM blended films: (a) 1, 1:0.6 (w/w); (b) 2, 1:0.6 (w/w); (c...
Figure 5: J–V curves of COOP-nHT-TBDT:PC61BM-based hole-only devices.
Figure 6: (a) VOC, (b) JSC, (c) FF, and (d) PCE decay of the COOP-nHT-TBDT:PC61BM solar cells. Note all these...
Beilstein J. Org. Chem. 2016, 12, 1512–1550, doi:10.3762/bjoc.12.148
Graphical Abstract
Scheme 1: Schematic description of the cyclisation reaction catalysed by TE domains. In most cases, the nucle...
Scheme 2: Mechanisms for the formation of oxygen heterocycles. The degree of substitution can differ from tha...
Scheme 3: Pyran-ring formation in pederin (24) biosynthesis. Incubation of recombinant PedPS7 with substrate ...
Scheme 4: The domain AmbDH3 from ambruticin biosynthesis catalyses the dehydration of 25 and subsequent cycli...
Scheme 5: SalBIII catalyses dehydration of 29 and subsequent cyclisation to tetrahydropyran 30 [18].
Figure 1: All pyranonaphtoquinones contain either the naphtha[2,3-c]pyran-5,10-dione (32) or the regioisomeri...
Scheme 6: Pyran-ring formation in actinorhodin (34) biosynthesis. DNPA: 4-dihydro-9-hydroxy-1-methyl-10-oxo-3H...
Scheme 7: Pyran formation in granaticin (36) biosynthesis. DNPA: 4-dihydro-9-hydroxy-1-methyl-10-oxo-3H-napht...
Scheme 8: Pyran formation in alnumycin (37) biosynthesis. Adapted from [21].
Scheme 9: Biosynthesis of pseudomonic acid A (61). The pyran ring is initially formed in 57 after dehydrogena...
Scheme 10: Epoxidation–cyclisation leads to the formation of the tetrahydropyran ring in the western part of t...
Scheme 11: a) Nonactin (70) is formed from heterodimers of (−)(+)-dimeric nonactic acid and (+)(−)-dimeric non...
Figure 2: Pamamycins (73) are macrodiolide antibiotics containing three tetrahydrofuran moieties, which are a...
Scheme 12: A PS domain homolog in oocydin A (76) biosynthesis is proposed to catalyse furan formation via an o...
Scheme 13: Mechanism of oxidation–furan cyclisation by AurH, which converts (+)-deoxyaureothin (77) into (+)-a...
Scheme 14: Leupyrrin A2 (80) and the proposed biosynthesis of its furylidene moiety [69,70].
Scheme 15: Asperfuranone (93) biosynthesis, adapted from [75].
Figure 3: The four major aflatoxins produced by Aspergilli are the types B1, B2, G1 and G2 (94–97). In the di...
Scheme 16: Overview on aflatoxin B1 (94) biosynthesis. HOMST = 11-hydroxy-O-methylsterigmatocystin [78,79,82-106].
Scheme 17: A zipper mechanism leads to the formation of oxygen heterocycles in monensin biosynthesis [109-111].
Scheme 18: Formation of the 2,6-dioxabicyclo[3.2.1]octane (DBO) ring system in aurovertin B (118) biosynthesis ...
Figure 4: Structures of the epoxide-containing polyketides epothilone A (119) and oleandomycin (120) [123-125].
Scheme 19: Structures of phoslactomycin B (121) (a) and jerangolid A (122) (b). The heterocycle-forming steps ...
Scheme 20: a) Structures of rhizoxin (130) and cycloheximide (131). Model for the formation of δ-lactones (b) ...
Scheme 21: EncM catalyses a dual oxidation sequence and following processing of the highly reactive intermedia...
Figure 5: Mesomeric structures of tetronates [138,139].
Figure 6: Structures of tetronates for which gene clusters have been sequenced. The tetronate moiety is shown...
Scheme 22: Conserved steps for formation and processing in several 3-acyl-tetronate biosynthetic pathways were...
Scheme 23: In versipelostatin A (153) biosynthesis, VstJ is a candidate enzyme for catalysing the [4 + 2] cycl...
Scheme 24: a) Structures of some thiotetronate antibiotics. b) Biosynthesis of thiolactomycin (165) as propose...
Scheme 25: Aureusidine synthase (AS) catalyses phenolic oxidation and conjugate addition of chalcones leading ...
Scheme 26: a) Oxidative cyclisation is a key step in the biosynthesis of spirobenzofuranes 189, 192 and 193. b...
Scheme 27: A bicyclisation mechanism forms a β-lactone and a pyrrolidinone and removes the precursor from the ...
Scheme 28: Spontaneous cyclisation leads to off-loading of ebelactone A (201) from the PKS machinery [163].
Scheme 29: Mechanisms for the formation of nitrogen heterocycles.
Scheme 30: Biosynthesis of highly substituted α-pyridinones. a) Feeding experiments confirmed the polyketide o...
Scheme 31: Acridone synthase (ACS) catalyses the formation of 1,3-dihydroxy-N-methylacridone (224) by condensa...
Scheme 32: A Dieckmann condensation leads to the formation of a 3-acyl-4-hydroxypyridin-2-one 227 and removes ...
Scheme 33: a) Biosynthesis of the pyridinone tenellin (234). b) A radical mechanism was proposed for the ring-...
Scheme 34: a) Oxazole-containing PKS–NRPS-derived natural products oxazolomycin (244) and conglobatin (245). b...
Scheme 35: Structure of tetramic acids 251 (a) and major tautomers of 3-acyltetramic acids 252a–d (b). Adapted...
Scheme 36: Equisetin biosynthesis. R*: terminal reductive domain. Adapted from [202].
Scheme 37: a) Polyketides for which a similar biosynthetic logic was suggested. b) Pseurotin A (256) biosynthe...
Figure 7: Representative examples of PTMs with varying ring sizes and oxidation patterns [205,206].
Scheme 38: Ikarugamycin biosynthesis. Adapted from [209-211].
Scheme 39: Tetramate formation in pyrroindomycin aglycone (279) biosynthesis [213-215].
Scheme 40: Dieckmann cyclases catalyse tetramate or 2-pyridone formation in the biosynthesis of, for example, ...
Beilstein J. Org. Chem. 2016, 12, 1493–1502, doi:10.3762/bjoc.12.146
Graphical Abstract
Scheme 1: Proposed routes for the three-component condensation [7].
Scheme 2: Synthetic methods for (aminomethylene)bisphosphonates I.
Scheme 3: Synthetic methods for (aminomethylene)bisphosphonates II.
Scheme 4: Synthetic methods for (aminomethylene)bisphosphine oxides.
Scheme 5: Synthesis of alkylamino- and (phenylaminomethylene)bisphosphine oxides.
Scheme 6: Synthesis of (dialkylaminomethylene)bisphosphine oxides.
Scheme 7: Synthesis of tetramethyl (phenylaminomethylene)bisphosphonate.
Scheme 8: Synthesis of (dialkylaminomethylene)bisphosphonates.
Figure 1: Effect of the quantity of dimethyl phosphite (DMP) on the product composition (from Table 6, entries 1–5.)
Figure 2: GC–MS chromatogram for the condensation of aniline, triethyl orthoformate and 2 equivalents of dime...
Figure 3: 31P NMR spectrum for the condensation of aniline, triethyl orthoformate and 2 equivalents of dibuty...
Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121
Graphical Abstract
Scheme 1: The Biginelli condensation.
Scheme 2: The Biginelli reaction of β-ketophosphonates catalyzed by ytterbium triflate.
Scheme 3: Trimethylchlorosilane-mediated Biginelli reaction of diethyl (3,3,3-trifluoropropyl-2-oxo)phosphona...
Scheme 4: Biginelli reaction of dialkyl (3,3,3-trifluoropropyl-2-oxo)phosphonate with trialkyl orthoformates ...
Scheme 5: p-Toluenesulfonic acid-promoted Biginelli reaction of β-ketophosphonates, aryl aldehydes and urea.
Scheme 6: General Kabachnik–Fields reaction for the synthesis of α-aminophosphonates.
Scheme 7: Phthalocyanine–AlCl catalyzed Kabachnik–Fields reaction of N-Boc-piperidin-4-one with diethyl phosp...
Scheme 8: Kabachnik–Fields reaction of isatin with diethyl phosphite and benzylamine.
Scheme 9: Magnetic Fe3O4 nanoparticle-supported phosphotungstic acid-catalyzed Kabachnik–Fields reaction of i...
Scheme 10: The Mg(ClO4)2-catalyzed Kabachnik–Fields reaction of 1-tosylpiperidine-4-one.
Scheme 11: An asymmetric version of the Kabachnik–Fields reaction for the synthesis of α-amino-3-piperidinylph...
Scheme 12: A classical Kabachnik–Fields reaction followed by an intramolecular ring-closing reaction for the s...
Scheme 13: Synthesis of (S)-piperidin-2-phosphonic acid through an asymmetric Kabachnik–Fields reaction.
Scheme 14: A modified diastereoselective Kabachnik–Fields reaction for the synthesis of isoindolin-1-one-3-pho...
Scheme 15: A microwave-assisted Kabachnik–Fields reaction toward isoindolin-1-ones.
Scheme 16: The synthesis of 3-arylmethyleneisoindolin-1-ones through a Horner–Wadsworth–Emmons reaction of Kab...
Scheme 17: An efficient one-pot method for the synthesis of ethyl (2-alkyl- and 2-aryl-3-oxoisoindolin-1-yl)ph...
Scheme 18: FeCl3 and PdCl2 co-catalyzed three-component reaction of 2-alkynylbenzaldehydes, anilines, and diet...
Scheme 19: Three-component reaction of 6-methyl-3-formylchromone (75) with hydrazine derivatives or hydroxylam...
Scheme 20: Three-component reaction of 6-methyl-3-formylchromone (75) with thiourea, guanidinium carbonate or ...
Scheme 21: Three-component reaction of 6-methyl-3-formylchromone (75) with 1,4-bi-nucleophiles in the presence...
Scheme 22: One-pot three-component reaction of 2-alkynylbenzaldehydes, amines, and diethyl phosphonate.
Scheme 23: Lewis acid–surfactant combined catalysts for the one-pot three-component reaction of 2-alkynylbenza...
Scheme 24: Lewis acid catalyzed cyclization of different Kabachnik–Fields adducts.
Scheme 25: Three-component synthesis of N-arylisoquinolone-1-phosphonates 119.
Scheme 26: CuI-catalyzed three-component tandem reaction of 2-(2-formylphenyl)ethanones with aromatic amines a...
Scheme 27: Synthesis of 1,5-benzodiazepin-2-ylphosphonates via ytterbium chloride-catalyzed three-component re...
Scheme 28: FeCl3-catalyzed four-component reaction for the synthesis of 1,5-benzodiazepin-2-ylphosphonates.
Scheme 29: Synthesis of indole bisphosphonates through a modified Kabachnik–Fields reaction.
Scheme 30: Synthesis of heterocyclic bisphosphonates via Kabachnik–Fields reaction of triethyl orthoformate.
Scheme 31: A domino Knoevenagel/phospha-Michael process for the synthesis of 2-oxoindolin-3-ylphosphonates.
Scheme 32: Intramolecular cyclization of phospha-Michael adducts to give dihydropyridinylphosphonates.
Scheme 33: Synthesis of fused phosphonylpyrans via intramolecular cyclization of phospha-Michael adducts.
Scheme 34: InCl3-catalyzed three-component synthesis of (2-amino-3-cyano-4H-chromen-4-yl)phosphonates.
Scheme 35: Synthesis of phosphonodihydropyrans via a domino Knoevenagel/hetero-Diels–Alder process.
Scheme 36: Multicomponent synthesis of phosphonodihydrothiopyrans via a domino Knoevenagel/hetero-Diels–Alder ...
Scheme 37: One-pot four-component synthesis of 1,2-dihydroisoquinolin-1-ylphosphonates under multicatalytic co...
Scheme 38: CuI-catalyzed four-component reactions of methyleneaziridines towards alkylphosphonates.
Scheme 39: Ruthenium–porphyrin complex-catalyzed three-component synthesis of aziridinylphosphonates and its p...
Scheme 40: Copper(I)-catalyzed three-component reaction towards 1,2,3-triazolyl-5-phosphonates.
Scheme 41: Three-component reaction of acylphosphonates, isocyanides and dialkyl acetylenedicarboxylate to aff...
Scheme 42: Synthesis of (4-imino-3,4-dihydroquinazolin-2-yl)phosphonates via an isocyanide-based three-compone...
Scheme 43: Silver-catalyzed three-component synthesis of (2-imidazolin-4-yl)phosphonates.
Scheme 44: Three-component synthesis of phosphonylpyrazoles.
Scheme 45: One-pot three-component synthesis of 3-carbo-5-phosphonylpyrazoles.
Scheme 46: A one-pot two-step method for the synthesis of phosphonylpyrazoles.
Scheme 47: A one-pot method for the synthesis of (5-vinylpyrazolyl)phosphonates.
Scheme 48: Synthesis of 1H-pyrrol-2-ylphosphonates via the [3 + 2] cycloaddition of phosphonate azomethine yli...
Scheme 49: Three-component synthesis of 1H-pyrrol-2-ylphosphonates.
Scheme 50: The classical Reissert reaction.
Scheme 51: One-pot three-component synthesis of N-phosphorylated isoquinolines.
Scheme 52: One-pot three-component synthesis of 1-acyl-1,2-dihydroquinoline-2-phosphonates and 2-acyl-1,2-dihy...
Scheme 53: Three-component reaction of pyridine derivatives with ethyl propiolate and dialkyl phosphonates.
Scheme 54: Three-component reactions for the phosphorylation of benzothiazole and isoquinoline.
Scheme 55: Three-component synthesis of diphenyl [2-(aminocarbonyl)- or [2-(aminothioxomethyl)-1,2-dihydroisoq...
Scheme 56: Three-component stereoselective synthesis of 1,2-dihydroquinolin-2-ylphosphonates and 1,2-dihydrois...
Scheme 57: Diphosphorylation of diazaheterocyclic compounds via a tandem 1,4–1,2 addition of dimethyl trimethy...
Scheme 58: Multicomponent reaction of alkanedials, acetamide and acetyl chloride in the presence of PCl3 and a...
Scheme 59: An oxidative domino three-component synthesis of polyfunctionalized pyridines.
Scheme 60: A sequential one-pot three-component synthesis of polysubstituted pyrroles.
Scheme 61: Three-component decarboxylative coupling of proline with aldehydes and dialkyl phosphites for the s...
Scheme 62: Three-component domino aza-Wittig/phospha-Mannich sequence for the phosphorylation of isatin deriva...
Scheme 63: Stereoselective synthesis of phosphorylated trans-1,5-benzodiazepines via a one-pot three-component...
Scheme 64: One-pot three-component synthesis of phosphorylated 2,6-dioxohexahydropyrimidines.
Beilstein J. Org. Chem. 2016, 12, 1072–1078, doi:10.3762/bjoc.12.101
Graphical Abstract
Scheme 1: Selected benzothiadaiazine 1,1-dioxides with potent biological activities.
Scheme 2: Scope of acetophenones (reaction conditions: 1 (0.33 mmol), 2a (0.3 mmol), DMSO (2 mL), I2 (0.75 eq...
Scheme 3: Scope of 2-aminobenzenesulfonamides (reaction conditions: 1 (0.33 mmol), 2a (0.3 mmol), DMSO (2 mL)...
Scheme 4: Reactions of 2-aminobenzenesulfonamides bearing an alknyl group (reaction conditions: 1 (0.33 mmol)...
Scheme 5: Gram scale reaction between 1a and 2a.
Figure 1: X-ray crystal structure of 4b (CCDC 1444753).
Scheme 6: Control experiment.
Scheme 7: Proposed mechanism.
Beilstein J. Org. Chem. 2016, 12, 846–853, doi:10.3762/bjoc.12.83
Graphical Abstract
Figure 1: P,N-ligand frameworks studied in this work.
Scheme 1: Synthesis of N-phosphanylformamidines 2 and 3. Reaction conditions: (i) t-BuLi, THF, −78 °C to rt, ...
Scheme 2: Synthesis of phosphanylformamidines 5 and 7. Reaction conditions: (i) t-BuLi, THF, −78 °C to rt, 1 ...
Scheme 3: Synthesis of complexes [2-M(cod)]X, [3-M(cod)]X, [5-M(cod)]X and [7-M(cod)]X. M = Rh, Ir; X = BF4− ...
Figure 2: Molecular structures of [2a-Rh(cod)]+ (A), [5-Ir(cod)]+ (B), and [7-Rh(cod)]+ (C,D). Anisotropic di...
Figure 3: Coordination of ligands 2a and 5 to Rh(III) and Ir(III) precursors. Yields: [2a-Cp*RhCl]BF4 = 87%, [...
Figure 4: Molecular structures of [2a-Cp*IrI]+ (left) and [5-Cp*IrI]+ (right). Anisotropic displacement ellip...
Figure 5: Formation of palladium complexes of ligands 2a, 5 and 7. (A) Formation of [2a-PdCl2] and [2a-PdCl]2...
Figure 6: Molecular structures of [2a-PdCl2] (left) and [5-Pd(2-Me-allyl)]+ (right). Anisotropic displacement...
Beilstein J. Org. Chem. 2016, 12, 571–588, doi:10.3762/bjoc.12.56
Graphical Abstract
Figure 1: Selected monocyclic and monobenzo α-pyrone structures.
Figure 2: The basic core structure of dibenzo-α-pyrones.
Figure 3: Selected dibenzo-α-pyrones.
Figure 4: Structure of ellagic acid and of the urolithins, the latter metabolized from ellagic acid by intest...
Figure 5: Structure of murayalactone, the only dibenzo-α-pyrone described from bacteria.
Figure 6: Structures of the 6-pentyl-2-pyrone (29) and of trichopyrone (30). Only 29 showed antifungal activi...
Figure 7: Selected monocyclic α-pyrones.
Figure 8: Structures of the gibepyrones A–F.
Figure 9: Structures of the phomenins A and B.
Figure 10: Structures of monocyclic α-pyrones showing pheromone (47) and antitumor activity (48), respectively....
Figure 11: Structures of 6-alkyl (alkoxy or alkylthio)-4-aryl-3-(4-methanesulfonylphenyl)pyrones.
Figure 12: Structures of kavalactones.
Figure 13: Strutures of germicins.
Figure 14: Structures of the pseudopyronines.
Figure 15: The structures of the monobenzo-α-pyrone anticoagulant drugs warfarin and phenprocoumon.
Figure 16: Structures of selected monobenzo-α-pyrones.
Figure 17: Hypothetical pathway of 29 generation from linoleic acid [34].
Figure 18: Proposed biosynthetic pathway of alternariol (modified from [77]). Malonyl-CoA building blocks are appl...
Figure 19: Structures of phenylnannolones and of enterocin, both biosynthesized via polyketide synthase system...
Figure 20: Pyrone ring formation. Examples for the three types of PKS systems are shown in A–C. In D the mecha...
Figure 21: Structures of csypyrones.
Figure 22: Schematic drawing of the T-shaped catalytic cavities of the related enzymes CorB and MxnB. The two ...
Figure 23: Stereo representation of the CorB binding situation (modified from [89]). The substrate mimic (dark vio...
Figure 24: Proposed mechanism for the CsyB enzymatic reaction. A) Coupling reaction of the β-keto fatty acyl i...
Figure 25: Proposed biosynthesis of photopyrone D (37) by the enzyme PpyS from P. luminescens (modified from [63])...
Beilstein J. Org. Chem. 2016, 12, 531–536, doi:10.3762/bjoc.12.52
Graphical Abstract
Figure 1: Halogenated anthraquinones.
Scheme 1: Initially proposed synthetic scheme for proisocrinins 6–11.
Scheme 2: Synthesis of cyanophthalide 12.
Scheme 3: Synthesis of cyclohexenone 13.
Scheme 4: Darzens condensation route to proisocrinins.
Scheme 5: Synthesis of cyclohexenone 36.
Scheme 6: Synthesis of the proisocrinin core structure.
Beilstein J. Org. Chem. 2016, 12, 444–461, doi:10.3762/bjoc.12.47
Graphical Abstract
Scheme 1: Breslow’s proposal on the mechanism of the benzoin condensation.
Scheme 2: Imidazolium carbene-catalysed homo-benzoin condensation.
Scheme 3: Homo-benzoin condensation in aqueous medium.
Scheme 4: Homobenzoin condensation catalysed by bis(benzimidazolium) salt 8.
Scheme 5: List of assorted chiral NHC-catalysts used for asymmetric homobenzoin condensation.
Scheme 6: A rigid bicyclic triazole precatalyst 15 in an efficient enantioselective benzoin reaction.
Scheme 7: Inoue’s report of cross-benzoin reactions.
Scheme 8: Cross-benzoin reactions catalysed by thiazolium salt 17.
Scheme 9: Catalyst-controlled divergence in cross-benzoin reactions.
Scheme 10: Chemoselective cross-benzoin reactions catalysed by a bulky NHC.
Scheme 11: Selective intermolecular cross-benzoin condensation reactions of aromatic and aliphatic aldehydes.
Scheme 12: Chemoselective cross-benzoin reaction of aliphatic and aromatic aldehydes.
Scheme 13: Cross-benzoin reactions of trifluoromethyl ketones developed by Enders.
Scheme 14: Cross-benzoin reactions of aldehydes and α-ketoesters.
Scheme 15: Enantioselective cross-benzoin reactions of aliphatic aldehydes and α-ketoesters.
Scheme 16: Dynamic kinetic resolution of β-halo-α-ketoesters via cross-benzoin reaction.
Scheme 17: Enantioselective benzoin reaction of aldehydes and alkynones.
Scheme 18: Aza-benzoin reaction of aldehydes and acylimines.
Scheme 19: NHC-catalysed diastereoselective synthesis of cis-2-amino 3-hydroxyindanones.
Scheme 20: Cross-aza-benzoin reactions of aldehydes with aromatic imines.
Scheme 21: Enantioselective cross aza-benzoin reaction of aliphatic aldehydes with N-Boc-imines.
Scheme 22: Chemoselective cross aza-benzoin reaction of aldehydes with N-PMP-imino esters.
Scheme 23: NHC-catalysed coupling reaction of acylsilanes with imines.
Scheme 24: Thiazolium salt-mediated enantioselective cross-aza-benzoin reaction.
Scheme 25: Aza-benzoin reaction of enals with activated ketimines.
Scheme 26: Isatin derived ketimines as electrophiles in cross aza-benzoin reaction with enals.
Scheme 27: Aza-benzoin reaction of aldehydes and phosphinoylimines catalysed by the BAC-carbene.
Scheme 28: Nitrosoarenes as the electrophilic component in benzoin-initiated cascade reaction.
Scheme 29: One-pot synthesis of hydroxamic esters via aza-benzoin reaction.
Scheme 30: Cookson and Lane’s report of intramolecular benzoin condensation.
Scheme 31: Intramolecular cross-benzoin condensation between aldehyde and ketone moieties.
Scheme 32: Intramolecular crossed aldehyde-ketone benzoin reactions.
Scheme 33: Enantioselective intramolecular crossed aldehyde-ketone benzoin reaction.
Scheme 34: Chromanone synthesis via enantioselective intramolecular cross-benzoin reaction.
Scheme 35: Intramolecular cross-benzoin reaction of chalcones.
Scheme 36: Synthesis of bicyclic tertiary alcohols by intramolecular benzoin reaction.
Scheme 37: A multicatalytic Michael–benzoin cascade process for cyclopentanone synthesis.
Scheme 38: Enamine-NHC dual-catalytic, Michael–benzoin cascade reaction.
Scheme 39: Iminium-cross-benzoin cascade reaction of enals and β-oxo sulfones.
Scheme 40: Intramolecular benzoin condensation of carbohydrate-derived dialdehydes.
Scheme 41: Enantioselective intramolecular benzoin reactions of N-tethered keto-aldehydes.
Scheme 42: Asymmetric cross-benzoin reactions promoted by camphor-derived catalysts.
Scheme 43: NHC-Brønsted base co-catalysis in a benzoin–Michael–Michael cascade.
Scheme 44: Divergent catalytic dimerization of 2-formylcinnamates.
Scheme 45: One-pot, multicatalytic asymmetric synthesis of tetrahydrocarbazole derivatives.
Scheme 46: NHC-chiral secondary amine co-catalysis for the synthesis of complex spirocyclic scaffolds.
Beilstein J. Org. Chem. 2015, 11, 2493–2508, doi:10.3762/bjoc.11.271
Graphical Abstract
Figure 1: Structures of lovastatin (1), aflatoxin B1 (2) and amphotericin B (3).
Scheme 1: a) Structure of rhizoxin (4). b) Two possible mechanisms of chain branching catalysed by a branchin...
Scheme 2: Structure of coelimycin P1 (8) and proposed biosynthetic formation from the putative PKS produced a...
Scheme 3: Structure of trioxacarcin A (9) with highlighted carbon origins of the polyketide core from acetate...
Scheme 4: Proposed biosynthetic assembly of clostrubin A (12). Bold bonds show intact acetate units.
Figure 2: Structure of forazoline A (13).
Figure 3: Structures of tyrocidine A (14) and teixobactin (15).
Figure 4: Top: Structure of the NRPS product kollosin A (16) with the sequence N-formyl-D-Leu-L-Ala-D-Leu-L-V...
Scheme 5: Proposed biosynthesis of aspirochlorine (20) via 18 and 19.
Scheme 6: Two different macrocyclization mechanisms in the biosynthesis of pyrrocidine A (24).
Figure 5: Structure of thiomarinol A (27). Bold bonds indicate carbon atoms derived from 4-hydroxybutyrate.
Figure 6: Structures of artemisinin (28), ingenol (29) and paclitaxel (30).
Figure 7: The revised (31) and the previously suggested (32) structure of hypodoratoxide and the structure of...
Figure 8: Structure of the two interconvertible conformers of (1(10)E,4E)-germacradien-6-ol (34) studied with...
Scheme 7: Proposed cyclization mechanism of corvol ethers A (42) and B (43) with the investigated reprotonati...
Scheme 8: Predicted (top) and observed (bottom) 13C-labeling pattern in cyclooctatin (45) after feeding of [U-...
Scheme 9: Proposed mechanism of the cyclooctat-9-en-7-ol (52) biosynthesis catalysed by CotB2. Annotated hydr...
Scheme 10: Cyclization mechanism of sesterfisherol (59). Bold lines indicate acetate units; black circles repr...
Scheme 11: Cyclization mechanisms to pentalenene (65) and protoillud-6-ene (67).
Scheme 12: Reactions of chorismate catalyzed by three different enzyme subfamilies. Oxygen atoms originating f...
Scheme 13: Incorporation of sulfur into tropodithietic acid (72) via cysteine.
Scheme 14: Biosynthetic proposal for the starter unit of antimycin biosynthesis. The hydrogens at positions R1...
Beilstein J. Org. Chem. 2015, 11, 1163–1174, doi:10.3762/bjoc.11.131
Graphical Abstract
Scheme 1: Proposed mechanisms via pathways (I) to (III) for the cathodic hydrodimerization of olefins with el...
Scheme 2: Cathodic reduction of nitroalkene 1 to hydrodimer 2 and oxime 5.
Scheme 3: Preparation of the 1-aryl-2-nitroalkenes 1, 4, 8–15.
Scheme 4: Reduction potentials (Ep,c in Volt) of nitroolefins. Conditions: amalgamated gold wire, v = 0.1 V/s...
Figure 1: (a) CV of 15; v = 0.1 V/s, (b) CV of 15; v = 10 V/s.
Scheme 5: Hydrodimerization of nitroalkene 14 and 15.
Scheme 6: (a) Intramolecular hydrocoupling of dinitrodiene 16 and (b) hydrodimerization of 1-nitrocyclohexene...
Scheme 7: Possible stereoisomers and their mirror images for the hydrodimers 2 and 18–23; R and S are the con...
Figure 2: 1H NMR spectrum of 18b (without aromatic H); below experimental spectrum, above: simulated signals ...
Beilstein J. Org. Chem. 2015, 11, 730–738, doi:10.3762/bjoc.11.83
Graphical Abstract
Scheme 1: Synthesis of hyperbranched polyglycerol-supported and G1 dendronized imidazolidin-4-ones 4a–c and 8...
Scheme 2: Synthesis of tyrosine-based imidazolidin-4-one 5. Reaction conditions: (a) 9 (1.0 equiv), MeNH2 (5....
Beilstein J. Org. Chem. 2015, 11, 499–503, doi:10.3762/bjoc.11.56
Graphical Abstract
Figure 1: Structures of the glycosylated heterocyclic GP inhibitors and corresponding Ki values against RMGPb....
Figure 2: Structures of the two targeted 3-glucosyl-5-amino-1,2,4-oxadiazoles.
Scheme 1: Synthesis of 3-glucosyl-5-amino-1,2,4-oxadiazoles.
Beilstein J. Org. Chem. 2014, 10, 3019–3030, doi:10.3762/bjoc.10.320
Graphical Abstract
Scheme 1: Some three-component reactions involving N-aryl-3-oxobutanamides.
Scheme 2: Some Biginelli-type three-component condensations with salicylaldehyde.
Scheme 3: Three-component heterocyclization of 5-amino-3-methylisoxazole (1), salicylaldehyde (2) and N-(2-me...
Figure 1: The possible structure of an intermediate complex in reactions forming the heterocycles 6.
Scheme 4: Possible pathways for the three-component reaction of 5-amino-3-methylisoxazole (1), salicylaldehyd...
Figure 2: Alternative structures 5a and 5'a for dihydroisoxazolopyridine 5a and selected NOESY correlations.
Figure 3: Alternative structures 6a, 6'a and 6''a for compound 6a.
Figure 4: Selected data from NOESY experiments and relative stereochemistry of stereogenic centers at positio...
Figure 5: Molecular structure of compound 6a according to X-ray diffraction data.
Beilstein J. Org. Chem. 2014, 10, 2021–2026, doi:10.3762/bjoc.10.210
Graphical Abstract
Scheme 1: [2.2]Paracyclophane derivatives with annelated alicyclic rings.
Scheme 2: The formation of the tetraketone 9 by a Diels–Alder addition.
Scheme 3: The possible structures of the aldols formed from 9.
Figure 1: Structure of 12·CDCl3 in the crystal. Ellipsoids represent 50% probability levels. Selected bond le...
Scheme 4: The mechanism of the aldol cyclization.
Scheme 5: Dehydration of the aldol 12.
Scheme 6: Dehydration of the aldol 15.
Figure 2: Structure of compound 21 in the crystal. Ellipsoids represent 50% probability levels. Selected bond...
Beilstein J. Org. Chem. 2014, 10, 1657–1669, doi:10.3762/bjoc.10.173
Graphical Abstract
Figure 1: The structures of purine nucleosides studied in the chemoenzymatic synthesis and in a cascade one-p...
Scheme 1: Chemical synthesis of 2-deoxy-2-fluoro-α/β-D-arabinofuranose-1-phosphates (12a,b). Reagents and con...
Figure 2: The structures of 1-phosphates of α-D-arabinofuranose (13a; AraFur-1P) and β-D-arabinopyranose (13b...
Figure 3: Geometry optimization of 1-phosphates of 2-deoxy-2-fluoro-α-D-arabinofuranose (12a) and the β-anome...
Figure 4: Progress of the formation of 9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-2-chloroadenine (1), 2-amino...
Figure 5: Clofarabine content in the reaction mixture vs time (hours) of the reaction.
Scheme 2: Suggested mechanism of purine nucleoside synthesis catalyzed by E. coli purine nucleoside phosphory...
Figure 6: Progress of the formation of β-D-arabinofuranosides and 2-deoxy-2-fluoro-β-D-arabinofuranosides of ...
Figure 7: Tautomeric structures of 5-aza-7-deazaguanine (17).
Figure 8: Progress of the formation of clofarabine (1), 9-(β-D-arabinofuranosyl)-2-chloroadenine (6), 9-(β-D-...
Beilstein J. Org. Chem. 2014, 10, 599–612, doi:10.3762/bjoc.10.51
Graphical Abstract
Figure 1: Linear push–pull solid-state diene lumophores with conformationally flexible and fixed acceptor moi...
Scheme 1: Three-component synthesis of 1-styryleth-2-enylideneindolones 8.
Figure 2: DFT-computed energy differences of the stereoisomers of 2Z,4Z-8a and 2Z,4E-8a.
Scheme 2: Three-component synthesis of 4-(1,3,3-trimethylindolin-2-ylidene)but-2-en-1-ylideneindolones 10.
Figure 3: DFT-computed energy differences of the stereoisomers of 10a and 10h.
Scheme 3: Mechanistic rationale of the three-component sequence furnishing the 1-styryleth-2-enylideneindolon...
Figure 4: DFT-computed (B3LYP functional, 6-31G* basis set) HOMO (left) and LUMO (right) of merocyanine 8a.
Figure 5: Absorption and emission spectrum of the dropcasted film of compound 8a (recorded at room temperatur...
Figure 6: Absorption spectrum of the dropcasted film of compound 10d (recorded at room temperature, normalize...
Figure 7: Absorption spectra of compound 10h in dichloromethane (right trace) and of the dropcasted film (lef...
Figure 8: DFT-computed (B3LYP functional, 6-311G(d,p) basis set) FMOs (HOMO, bottom; LUMO (center), and LUMO+...
Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50
Graphical Abstract
Scheme 1: The proposed mechanism of the Passerini reaction.
Scheme 2: The PADAM-strategy to α-hydroxy-β-amino amide derivatives 7. An additional oxidation provides α-ket...
Scheme 3: The general accepted Ugi-mechanism.
Scheme 4: Three commonly applied Ugi/cyclization approaches. a) UDC-process, b) UAC-sequence, c) UDAC-combina...
Scheme 5: Ugi reaction that involves the condensation of Armstrong’s convertible isocyanide.
Scheme 6: Mechanism of the U-4C-3CR towards bicyclic β-lactams.
Scheme 7: The Ugi 4C-3CR towards oxabicyclo β-lactams.
Scheme 8: Ugi MCR between an enantiopure monoterpene based β-amino acid, aldehyde and isocyanide resulting in...
Scheme 9: General MCR for β-lactams in water.
Scheme 10: a) Ugi reaction for β-lactam-linked peptidomimetics. b) Varying the β-amino acid resulted in β-lact...
Scheme 11: Ugi-4CR followed by a Pd-catalyzed Sn2 cyclization.
Scheme 12: Ugi-3CR of dipeptide mimics from 2-substituted pyrrolines.
Scheme 13: Joullié–Ugi reaction towards 2,5-disubstituted pyrrolidines.
Scheme 14: Further elaboration of the Ugi-scaffold towards bicyclic systems.
Scheme 15: Dihydroxyproline derivatives from an Ugi reaction.
Scheme 16: Diastereoselective Ugi reaction described by Banfi and co-workers.
Scheme 17: Similar Ugi reaction as in Scheme 16 but with different acids and two chiral isocyanides.
Scheme 18: Highly diastereoselective synthesis of pyrrolidine-dipeptoids via a MAO-N/MCR-procedure.
Scheme 19: MAO-N/MCR-approach towards the hepatitis C drug telaprevir.
Scheme 20: Enantioselective MAO-U-3CR procedure starting from chiral pyrroline 64.
Scheme 21: Synthesis of γ-lactams via an UDC-sequence.
Scheme 22: Utilizing bifunctional groups to provide bicyclic γ-lactam-ketopiperazines.
Scheme 23: The Ugi reaction provided both γ- as δ-lactams depending on which inputs were used.
Scheme 24: The sequential Ugi/RCM with olefinic substrates provided bicyclic lactams.
Scheme 25: a) The structural and dipole similarities of the triazole unit with the amide bond. b) The copper-c...
Scheme 26: The Ugi/Click sequence provided triazole based peptidomimetics.
Scheme 27: The Ugi/Click reaction as described by Nanajdenko.
Scheme 28: The Ugi/Click-approach by Pramitha and Bahulayan.
Scheme 29: The Ugi/Click-combination by Niu et al.
Scheme 30: Triazole linked peptidomimetics obtained from two separate MCRs and a sequential Click reaction.
Scheme 31: Copper-free synthesis of triazoles via two MCRs in one-pot.
Scheme 32: The sequential Ugi/Paal–Knorr reaction to afford pyrazoles.
Scheme 33: An intramolecular Paal–Knorr condensation provided under basic conditions pyrazolones.
Scheme 34: Similar cyclization performed under acidic conditions provided pyrazolones without the trifluoroace...
Scheme 35: The Ugi-4CR towards 2,4-disubstituted thiazoles.
Scheme 36: Solid phase approach towards thiazoles.
Scheme 37: Reaction mechanism of formation of thiazole peptidomimetics containing an additional β-lactam moiet...
Scheme 38: The synthesis of the trisubstituted thiazoles could be either performed via an Ugi reaction with pr...
Scheme 39: Performing the Ugi reaction with DMB-protected isocyanide gave access to either oxazoles or thiazol...
Scheme 40: Ugi/cyclization-approach towards 2,5-disubstituted thiazoles. The Ugi reaction was performed with d...
Scheme 41: Further derivatization of the thiazole scaffold.
Scheme 42: Three-step procedure towards the natural product bacillamide C.
Scheme 43: Ugi-4CR to oxazoles reported by Zhu and co-workers.
Scheme 44: Ugi-based synthesis of oxazole-containing peptidomimetics.
Scheme 45: TMNS3 based Ugi reaction for peptidomimics containing a tetrazole.
Scheme 46: Catalytic cycle of the enantioselective Passerini reaction towards tetrazole-based peptidomimetics.
Scheme 47: Tetrazole-based peptidomimetics via an Ugi reaction and a subsequent sigmatropic rearrangement.
Scheme 48: Resin-bound Ugi-approach towards tetrazole-based peptidomimetics.
Scheme 49: Ugi/cyclization approach towards γ/δ/ε-lactam tetrazoles.
Scheme 50: Ugi-3CR to pipecolic acid-based peptidomimetics.
Scheme 51: Staudinger–Aza-Wittig/Ugi-approach towards pipecolic acid peptidomimetics.
Figure 1: The three structural isomers of diketopiperazines. The 2,5-DKP isomer is most common.
Scheme 52: UDC-approach to obtain 2,5-DKPs, either using Armstrong’s isocyanide or via ethylglyoxalate.
Scheme 53: a) Ugi reaction in water gave either 2,5-DKP structures or spiro compounds. b) The Ugi reaction in ...
Scheme 54: Solid-phase approach towards diketopiperazines.
Scheme 55: UDAC-approach towards DKPs.
Scheme 56: The intermediate amide is activated as leaving group by acid and microwave assisted organic synthes...
Scheme 57: UDC-procedure towards active oxytocin inhibitors.
Scheme 58: An improved stereoselective MCR-approach towards the oxytocin inhibitor.
Scheme 59: The less common Ugi reaction towards DKPs, involving a Sn2-substitution.
Figure 2: Spatial similarities between a natural β-turn conformation and a DKP based β-turn mimetic [158].
Scheme 60: Ugi-based syntheses of bicyclic DKPs. The amine component is derived from a coupling between (R)-N-...
Scheme 61: Ugi-based synthesis of β-turn and γ-turn mimetics.
Figure 3: Isocyanide substituted 3,4-dihydropyridin-2-ones, dihydropyridines and the Freidinger lactams. Bio-...
Scheme 62: The mechanism of the 4-CR towards 3,4-dihydropyridine-2-ones 212.
Scheme 63: a) Multiple MCR-approach to provide DHP-peptidomimetic in two-steps. b) A one-pot 6-CR providing th...
Scheme 64: The MCR–alkylation–MCR procedure to obtain either tetrapeptoids or depsipeptides.
Scheme 65: U-3CR/cyclization employing semicarbazone as imine component gave triazine based peptidomimetics.
Scheme 66: 4CR towards triazinane-diones.
Scheme 67: The MCR–alkylation–IMCR-sequence described by our group towards triazinane dione-based peptidomimet...
Scheme 68: Ugi-4CR approaches followed by a cyclization to thiomorpholin-ones (a) and pyrrolidines (b).
Scheme 69: UDC-approach for benzodiazepinones.
Scheme 70: Ugi/Mitsunobu sequence to BDPs.
Scheme 71: A UDAC-approach to BDPs with convertible isocyanides. The corresponding amide is cleaved by microwa...
Scheme 72: microwave assisted post condensation Ugi reaction.
Scheme 73: Benzodiazepinones synthesized via the post-condensation Ugi/ Staudinger–Aza-Wittig cyclization.
Scheme 74: Two Ugi/cyclization approaches utilizing chiral carboxylic acids. Reaction (a) provided the product...
Scheme 75: The mechanism of the Gewald-3CR includes three base-catalysed steps involving first a Knoevnagel–Co...
Scheme 76: Two structural 1,4-thienodiazepine-2,5-dione isomers by U-4CR/cyclization.
Scheme 77: Tetrazole-based diazepinones by UDC-procedure.
Scheme 78: Tetrazole-based BDPs via a sequential Ugi/hydrolysis/coupling.
Scheme 79: MCR synthesis of three different tricyclic BPDs.
Scheme 80: Two similar approaches both involving an Ugi reaction and a Mitsunobu cyclization.
Scheme 81: Mitsunobu–Ugi-approach towards dihydro-1,4-benzoxazepines.
Scheme 82: Ugi reaction towards hetero-aryl fused 5-oxo-1,4-oxazepines.
Scheme 83: a) Ugi/RCM-approach towards nine-membered peptidomimetics b) Sequential peptide-coupling, deprotect...
Scheme 84: Ugi-based synthesis towards cyclic RGD-pentapeptides.
Scheme 85: Ugi/MCR-approach towards 12–15 membered macrocycles.
Scheme 86: Stereoselective Ugi/RCM approach towards 16-membered macrocycles.
Scheme 87: Passerini/RCM-sequence to 22-membered macrocycles.
Scheme 88: UDAC-approach towards 12–18-membered depsipeptides.
Figure 4: Enopeptin A with its more active derivative ADEP-4.
Scheme 89: a) The Joullié–Ugi-approach towards ADEP-4 derivatives b) Ugi-approach for the α,α-dimethylated der...
Scheme 90: Ugi–Click-strategy for 15-membered macrocyclic glyco-peptidomimetics.
Scheme 91: Ugi/Click combinations provided macrocycles containing both a triazole and an oxazole moiety.
Scheme 92: a) A solution-phase procedure towards macrocycles. b) Alternative solid-phase synthesis as was repo...
Scheme 93: Ugi/cyclization towards cyclophane based macrocycles.
Scheme 94: PADAM-strategy towards eurystatin A.
Scheme 95: PADAM-approach for cyclotheanamide.
Scheme 96: A triple MCR-approach affording RGD-pentapeptoids.
Scheme 97: Ugi-MiBs-approach towards peptoid macrocycles.
Scheme 98: Passerini-based MiB approaches towards macrocycles 345 and 346.
Scheme 99: Macrocyclic peptide formation by the use of amphoteric aziridine-based aldehydes.
Beilstein J. Org. Chem. 2014, 10, 394–404, doi:10.3762/bjoc.10.37
Graphical Abstract
Scheme 1: Flögel-three-component reaction of lithiated alkoxyallenes, nitriles and carboxylic acids providing...
Scheme 2: Synthesis of bis(β-ketoenamides) 13–15 by three-component reactions of lithiated methoxyallene 8 wi...
Scheme 3: Cyclocondensations of β-ketoenamides 13 and 14 to 4-hydroxypyridines 16, 18a and 18b, their subsequ...
Scheme 4: Cyclocondensations of β-ketoenamides 13–15 with ammonium acetate to bis(pyrimidine) derivatives 23a...
Scheme 5: Conversion of mono-pyrimidine derivative 24b into unsymmetrically substituted biphenylen-bridged py...
Scheme 6: Condensation of β-ketoenamides 14 and 20 with hydroxylamine hydrochloride to pyridine-N-oxides 28 a...
Scheme 7: Riley oxidation of bis(pyrimidine) derivative 23a and conversion of diol 32a into macrocycle 34.
Figure 1: Optimized geometries of (a) E-configured and (b) Z-configured macrocycle 34 at B3LYP/6-31G(d,p) lev...
Scheme 8: Dihydroxylation of the macrocyclic olefin 34 to diol 35 and subsequent esterification to the bis-(R...
Beilstein J. Org. Chem. 2013, 9, 2586–2614, doi:10.3762/bjoc.9.294
Graphical Abstract
Figure 1: Elementary steps in the gold-catalyzed nucleophilic addition to olefins.
Figure 2: Different approaches for the gold-catalyzed manipulation of inactivated alkenes.
Figure 3: Computed mechanistic cycle for the gold-catalyzed alkoxylation of ethylene with PhOH.
Scheme 1: [Au(I)]-catalyzed addition of phenols and carboxylic acids to alkenes.
Scheme 2: [Au(III)] catalyzed annulations of phenols and naphthols with dienes.
Scheme 3: [Au(III)]-catalyzed addition of aliphatic alcohols to alkenes.
Scheme 4: [Au(III)]-catalyzed carboalkoxylation of alkenes with dimethyl acetals 6.
Figure 4: Postulated mechanism for the [Au(I)]-catalyzed hydroamination of olefins.
Scheme 5: Isolation and reactivity of alkyl gold intermediates in the intramolecular hydroamination of alkene...
Scheme 6: [Au(I)]-catalyzed intermolecular hydroamination of dienes.
Scheme 7: Intramolecular [Au(I)]-catalyzed hydroamination of alkenes with carbamates.
Scheme 8: [Au(I)]-catalyzed inter- as well as intramolecular addition of sulfonamides to isolated alkenes.
Scheme 9: Intramolecular hydroamination of N-alkenylureas catalyzed by gold(I) carbene complex.
Scheme 10: Enantioselective hydroamination of alkenyl ureas with biphenyl tropos ligand and chiral silver phos...
Scheme 11: Intramolecular [Au(I)]-catalyzed hydroamination of N-allyl-N’-aryl ureas. (PNP = pNO2-C6H4, PMP = p...
Scheme 12: [Au(I)]-catalyzed hydroamination of alkenes with ammonium salts.
Scheme 13: Enantioselective [Au(I)]-catalyzed intermolecular hydroamination of alkenes with cyclic ureas.
Scheme 14: Mechanistic proposal for the cooperative [Au(I)]/menthol catalysis for the enantioselective intramo...
Scheme 15: [Au(III)]-catalyzed addition of 1,3-diketones to alkenes.
Scheme 16: [Au(I)]-catalyzed intramolecular addition of β-keto amides to alkenes.
Scheme 17: Intermolecular [Au(I)]-catalyzed addition of indoles to alkenes.
Scheme 18: Intermolecular [Au(III)]-catalyzed hydroarylation of alkenes with benzene derivatives and thiophene....
Scheme 19: a) Intramolecular [Au(III)]-catalyzed hydroarylation of alkenes. b) A SEAr-type mechanism was hypot...
Scheme 20: Intramolecular [Au(I)]-catalyzed hydroalkylation of alkenes with simple ketones.
Scheme 21: Proposed reaction mechanism for the intramolecular [Au(I)]-catalyzed hydroalkylation of alkenes wit...
Scheme 22: Tandem Michael addition/hydroalkylation catalyzed by [Au(I)] and [Ag(I)] salts.
Scheme 23: Intramolecular [Au(I)]-catalyzed tandem migration/[2 + 2] cycloaddition of 1,7-enyne benzoates.
Scheme 24: Intramolecular [Au(I)]-catalyzed cyclopropanation of alkenes.
Scheme 25: Stereospecificity in [Au(I)]-catalyzed hydroalkoxylation of allylic alcohols.
Scheme 26: Mechanistic investigation on the intramolecular [Au(I)]-catalyzed hydroalkoxylation of allylic alco...
Scheme 27: Mechanistic investigation on the intramolecular enantioselective [Au(I)]-catalyzed alkylation of in...
Scheme 28: Synthesis of (+)-isoaltholactone via stereospecific intramolecular [Au(I)]-catalyzed alkoxylation o...
Scheme 29: Intramolecular enantioselective dehydrative amination of allylic alcohols catalyzed by chiral [Au(I...
Scheme 30: Enantioselective intramolecular hydroalkylation of allylic alcohols with aldehydes catalyzed by 20c...
Scheme 31: Gold-catalyzed intramolecular diamination of alkenes.
Scheme 32: Gold-catalyzed aminooxygenation and aminoarylation of alkenes.
Scheme 33: Gold-catalyzed carboamination, carboalkoxylation and carbolactonization of terminal alkenes with ar...
Scheme 34: Synthesis of tricyclic indolines via gold-catalyzed formal [3 + 2] cycloaddition.
Scheme 35: Gold(I) catalyzed aminoarylation of terminal alkenes in presence of Selectfluor [dppm = bis(dipheny...
Scheme 36: Mechanistic investigation on the aminoarylation of terminal alkenes by bimetallic gold(I) catalysis...
Scheme 37: Proposed mechanism for the aminoarylation of alkenes via [Au(I)-Au(I)]/[Au(II)-Au(II)] redox cataly...
Scheme 38: Oxyarylation of terminal olefins via redox gold catalysis.
Scheme 39: a) Intramolecular gold-catalyzed oxidative coupling reactions with aryltrimethylsilanes. b) Oxyaryl...
Scheme 40: Oxy- and amino-arylation of alkenes by [Au(I)]/[Au(III)] photoredox catalysis.
Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265
Graphical Abstract
Scheme 1: Scaled industrial processes for the synthesis of simple pyridines.
Scheme 2: Synthesis of nicotinic acid from 2-methyl-5-ethylpyridine (1.11).
Scheme 3: Synthesis of 3-picoline and nicotinic acid.
Scheme 4: Synthesis of 3-picoline from 2-methylglutarodinitrile 1.19.
Scheme 5: Picoline-based synthesis of clarinex (no yields reported).
Scheme 6: Mode of action of proton-pump inhibitors and structures of the API’s.
Scheme 7: Hantzsch-like route towards the pyridine rings in common proton pump inhibitors.
Figure 1: Structures of rosiglitazone (1.40) and pioglitazone (1.41).
Scheme 8: Synthesis of rosiglitazone.
Scheme 9: Syntheses of 2-pyridones.
Scheme 10: Synthesis and mechanism of 2-pyrone from malic acid.
Scheme 11: Polymer-assisted synthesis of rosiglitazone.
Scheme 12: Synthesis of pioglitazone.
Scheme 13: Meerwein arylation reaction towards pioglitazone.
Scheme 14: Route towards pioglitazone utilising tyrosine.
Scheme 15: Route towards pioglitazone via Darzens ester formation.
Scheme 16: Syntheses of the thiazolidinedione moiety.
Scheme 17: Synthesis of etoricoxib utilising Negishi and Stille cross-coupling reactions.
Scheme 18: Synthesis of etoricoxib via vinamidinium condensation.
Figure 2: Structures of nalidixic acid, levofloxacin and moxifloxacin.
Scheme 19: Synthesis of moxifloxacin.
Scheme 20: Synthesis of (S,S)-2,8-diazabicyclo[4.3.0]nonane 1.105.
Scheme 21: Synthesis of levofloxacin.
Scheme 22: Alternative approach to the levofloxacin core 1.125.
Figure 3: Structures of nifedipine, amlodipine and clevidipine.
Scheme 23: Mg3N2-mediated synthesis of nifedipine.
Scheme 24: Synthesis of rac-amlodipine as besylate salt.
Scheme 25: Aza Diels–Alder approach towards amlodipine.
Scheme 26: Routes towards clevidipine.
Figure 4: Examples of piperidine containing drugs.
Figure 5: Discovery of tiagabine based on early leads.
Scheme 27: Synthetic sequences to tiagabine.
Figure 6: Structures of solifenacin (2.57) and muscarine (2.58).
Scheme 28: Enantioselective synthesis of solifenacin.
Figure 7: Structures of DPP-4 inhibitors of the gliptin-type.
Scheme 29: Formation of inactive diketopiperazines from cis-rotameric precursors.
Figure 8: Co-crystal structure of carmegliptin bound in the human DPP-4 active site (PDB 3kwf).
Scheme 30: Improved route to carmegliptin.
Figure 9: Structures of lamivudine and zidovudine.
Scheme 31: Typical routes accessing uracil, thymine and cytosine.
Scheme 32: Coupling between pyrimidones and riboses via the Vorbrüggen nucleosidation.
Scheme 33: Synthesis of lamivudine.
Scheme 34: Synthesis of raltegravir.
Scheme 35: Mechanistic studies on the formation of 3.22.
Figure 10: Structures of selected pyrimidine containing drugs.
Scheme 36: General preparation of pyrimidines and dihydropyrimidones.
Scheme 37: Synthesis of imatinib.
Scheme 38: Flow synthesis of imatinib.
Scheme 39: Syntheses of erlotinib.
Scheme 40: Synthesis of erlotinib proceeding via Dimroth rearrangement.
Scheme 41: Synthesis of lapatinib.
Scheme 42: Synthesis of rosuvastatin.
Scheme 43: Alternative preparation of the key aldehyde towards rosuvastatin.
Figure 11: Structure comparison between nicotinic acetylcholine receptor agonists.
Scheme 44: Syntheses of varenicline and its key building block 4.5.
Scheme 45: Synthetic access to eszopiclone and brimonidine via quinoxaline intermediates.
Figure 12: Bortezomib bound in an active site of the yeast 20S proteasome ([114], pdb 2F16).
Scheme 46: Asymmetric synthesis of bortezomib.
Figure 13: Structures of some prominent piperazine containing drugs.
Figure 14: Structural comparison between the core of aplaviroc (4.35) and a type-1 β-turn (4.36).
Scheme 47: Examplary synthesis of an aplaviroc analogue via the Ugi-MCR.
Scheme 48: Syntheses of azelastine (5.1).
Figure 15: Structures of captopril, enalapril and cilazapril.
Scheme 49: Synthesis of cilazapril.
Figure 16: Structures of lamotrigine, ceftriaxone and azapropazone.
Scheme 50: Synthesis of lamotrigine.
Scheme 51: Alternative synthesis of lamotrigine (no yields reported).
Figure 17: Structural comparison between imiquimod and the related adenosine nucleoside.
Scheme 52: Conventional synthesis of imiquimod (no yields reported).
Scheme 53: Synthesis of imiquimod.
Scheme 54: Synthesis of imiquimod via tetrazole formation (not all yields reported).
Figure 18: Structures of various anti HIV-medications.
Scheme 55: Synthesis of abacavir.
Figure 19: Structures of diazepam compared to modern replacements.
Scheme 56: Synthesis of ocinaplon.
Scheme 57: Access to zaleplon and indiplon.
Scheme 58: Different routes towards the required N-methylpyrazole 6.65 of sildenafil.
Scheme 59: Polymer-supported reagents in the synthesis of key aminopyrazole 6.72.
Scheme 60: Early synthetic route to sildenafil.
Scheme 61: Convergent preparations of sildenafil.
Figure 20: Comparison of the structures of sildenafil, tadalafil and vardenafil.
Scheme 62: Short route to imidazotriazinones.
Scheme 63: Alternative route towards vardenafils core imidazotriazinone (6.95).
Scheme 64: Bayer’s approach to the vardenafil core.
Scheme 65: Large scale synthesis of vardenafil.
Scheme 66: Mode of action of temozolomide (6.105) as methylating agent.
Scheme 67: Different routes to temozolomide.
Scheme 68: Safer route towards temozolomide.
Figure 21: Some unreported heterocyclic scaffolds in top market drugs.
Beilstein J. Org. Chem. 2013, 9, 1843–1852, doi:10.3762/bjoc.9.215
Graphical Abstract
Figure 1: (a) Flow cell and (b) Raman interface used in the present study.
Scheme 1: The reaction between salicylaldehyde and ethyl acetoacetate to form 3-acetyl coumarin (1).
Figure 2: The Raman spectrum of 3-acetylcoumarin (1) generated using Gaussian 09 [40] at the B3LYP/6-31g(d) level...
Figure 3: Monitoring an aliquot of 3-acetyl coumarin (1) as it passes through the flow cell (scan time = 15 s...
Figure 4: Monitoring the conversion of salicylaldehyde and ethyl acetoacetate to 3-acetylcoumarin (1) across ...
Figure 5: Plot of Raman intensity of the peak arising at 1608 cm-1 vs concentration of 3-acetyl coumarin (1),...
Scheme 2: The Knoevenagel condensation of benzaldehyde and ethyl acetoacetate to yield (Z)-ethyl 2-benzyliden...
Figure 6: Monitoring the conversion of benzaldehyde and ethyl acetoacetate to (Z)-ethyl 2-benzylidene-3-oxobu...
Scheme 3: Claisen-Schmidt condensation of benzaldehyde with acetophenone to yield chalcone, 3a.
Figure 7: Monitoring the conversion of benzaldehyde with acetophenone to chalcone, 3a, across a range of reac...
Scheme 4: The Biginelli cyclocondensation of benzaldehyde, ethyl acetoacetate, and urea to yield 5-ethoxycarb...
Figure 8: Monitoring the conversion of benzaldehyde, ethyl acetoacetate, and urea to 5-ethoxycarbonyl-6-methy...