CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

Rh(II)-mediated domino [4 + 1]-annulation of α-cyanothioacetamides using diazoesters: A new entry for the synthesis of multisubstituted thiophenes

• Jury J. Medvedev,
• Ilya V. Efimov,
• Yuri M. Shafran,
• Vitaliy V. Suslonov,
• Vasiliy A. Bakulev and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2017, 13, 2569–2576, doi:10.3762/bjoc.13.253

• ’, as illustrated in Scheme 4. Initially generated from diazoester 2 carbenoid A attacks the sulfur atom of thioamide 1 to give the key intermediate S-ylide B [36][37][38][59][60], which is stabilized by ‘thioamide resonance’ [36][37][38]. The anion center of S-ylide B then attacks the carbon atom of

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• syntheses of alstilobanines A, E and angustilodine, functionalized indole 33 was initially chosen as a key intermediate [33]. However, attempts of its preparation by Michael addition of substituted indole enolate 34 to nitrosoalkene NSA8, generated in situ either from the corresponding chlorooxime 35 or its

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• would form as the key intermediate. Upon dissociation of the anomeric C–S bond of the sulfonium intermediate 102, an oxygen nucleophile on the boronate ester would attack the C-1 center on the opposite side resulting in 103 with good stereoselection (Scheme 23). Initial trials with 3-methylbenzyl

A novel application of 2-silylated 1,3-dithiolanes for the synthesis of aryl/hetaryl-substituted ethenes and dibenzofulvenes

• Grzegorz Mlostoń,
• Paulina Pipiak,
• Róża Hamera-Fałdyga and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 1900–1906, doi:10.3762/bjoc.13.185

• chemistry and related sciences. The key intermediate in the reaction is the 1,3-dithiolane carbanion, which, in contrast to the 4,5-unsubstituted analogues, undergoes a spontaneous cycloreversion reaction to give tetraarylethene and dithioformate anion. This method supplements the list of preparatively

Influence of the milling parameters on the nucleophilic substitution reaction of activated β-cyclodextrins

• László Jicsinszky,
• Kata Tuza,
• Giancarlo Cravotto,
• Andrea Porcheddu,
• Francesco Delogu and
• Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 1893–1899, doi:10.3762/bjoc.13.184

• differences are also elements of complexity. The mechanical processing of CDs in the absence of solvent therefore promises to simplify the work-up and allows the almost complete utilization of the CD key-intermediate [13], in comparison with the classic method [6]. Moreover, the absence of a solvent, high

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• of molecular oxygen and with catalytic copper acetate (Cu(OAc)2) generated the desired pyrimidine 102 which was converted to the final products in a few more steps. This is one of the noteworthy examples where oxidative dehydrogenation has been utilized for the synthesis of a key intermediate of an

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Development of a method for the synthesis of 2,4,5-trisubstituted oxazoles composed of carboxylic acid, amino acid, and boronic acid

• Kohei Yamada,
• Naoto Kamimura and
• Munetaka Kunishima

Beilstein J. Org. Chem. 2017, 13, 1478–1485, doi:10.3762/bjoc.13.146

• trisubstituted oxazoles. Herein, we described an efficient method for the synthesis of trisubstituted oxazoles through a one-pot oxazole synthesis and subsequent Suzuki–Miyaura coupling. Results and Discussion The study was initiated with the preparation of the key intermediate, 5-(triazinyloxy)oxazole 3, from

Synthesis of the heterocyclic core of the D-series GE2270

• Christophe Berini,
• Thibaut Martin,
• Pierrik Lassalas,
• Francis Marsais,
• Christine Baudequin and
• Christophe Hoarau

Beilstein J. Org. Chem. 2017, 13, 1407–1412, doi:10.3762/bjoc.13.137

• reported two-step oxidation/Reissert-type sequence [21][22]. The access to the key intermediate trithiazolylpyridine 9 was next investigated via two synthetic routes by exploiting BSC cross-coupling and Hantzsch condensation reactions from the picolinamide 5, which was produced by simple treatment of 6

• in fair 59% yield over 2 steps. Finally, the second synthetic pathway proved to be slightly more performant to produce the trithiazolylpyridine key-intermediate 9 from the picolinamide 5 in 58% yields over 3 steps (vs 55% for the first synthetic route). Then, the trithiazolylpyridine 9 was engaged in

• the key-intermediate 6-chloro-5-thiazolylpicolinate ester 4, which was obtained in multi-gram amounts in 57% yield over 3 synthetic steps (13% global yield) from the readily available ester ethyl 5-bromopicolinate (1) as starting material. Main synthetic strategies towards heterocyclic cores of D

Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions

• Adrián A. Heredia and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2017, 13, 910–918, doi:10.3762/bjoc.13.92

• afforded 64% yield of phenylacetylene (6a), while the elimination reaction was quantitative with 2 equiv of the base. These results suggested that 6a is a key intermediate in the reaction. Furthermore, the fact that in the presence of 1 equiv of base the elimination product was obtained in approximately 50

Fluorescent carbon dots from mono- and polysaccharides: synthesis, properties and applications

• Stephen Hill and
• M. Carmen Galan

Beilstein J. Org. Chem. 2017, 13, 675–693, doi:10.3762/bjoc.13.67

• observed. React-IR studies under hydrothermal conditions, but at a lower temperature of 70 °C, helped the team to identify a reactive iminium species, which is formed from the reaction between the sugar aldehyde and an amine present in the reaction mixture, and is a key intermediate in the initial stages

The reductive decyanation reaction: an overview and recent developments

• Jean-Marc R. Mattalia

Beilstein J. Org. Chem. 2017, 13, 267–284, doi:10.3762/bjoc.13.30

• . First, a SET from the electron donor to the nitrile forms a radical anion. This radical anion can fragment into a cyanide ion and a radical which is rapidly reduced into a stabilized carbanion before protonation. This carbanion appears as a key intermediate leading to complex mixtures when method A is

Total synthesis of a Streptococcus pneumoniae serotype 12F CPS repeating unit hexasaccharide

• Peter H. Seeberger,
• Claney L. Pereira and
• Subramanian Govindan

Beilstein J. Org. Chem. 2017, 13, 164–173, doi:10.3762/bjoc.13.19

• reducing to the non-reducing end (Scheme 8). Union of 4 and 5 (Scheme 7) produced disaccharide 41 as the key intermediate, the naphthyl protecting group of which was cleaved in 70% yield using DDQ [37] to afford 42. Thioglycoside 43 failed to react with disaccharide 42 to furnish the desired trisaccharide

Symmetry-based approach to oligostilbenoids: Rapid entry to viniferifuran, shoreaphenol, malibatol A, and diptoindonesin G

• Youngeun Jung,
• Dileep Kumar Singh and
• Ikyon Kim

Beilstein J. Org. Chem. 2016, 12, 2689–2693, doi:10.3762/bjoc.12.266

• ring toward the neighboring alkyne in the iodine-mediated cyclization reactions were explored. Starting from the symmetrical 3,5-dimethoxybenzyl alcohol, this route allowed rapid access to 2,3-diarylbenzofuran, a key intermediate to several oligostilbenoid natural products, in good overall yields

• element [19] of the target molecules. We expected that the key intermediate (inset box of Scheme 1) could be constructed from the monoiodo compounds 1, 2, or 3 through a sequence involving Sonogashira coupling, iodocyclization [20][21][22][23][24][25][26], and Suzuki coupling. As the starting materials (1

Facile synthesis of a 3-deazaadenosine phosphoramidite for RNA solid-phase synthesis

• Elisabeth Mairhofer,
• Elisabeth Fuchs and
• Ronald Micura

Beilstein J. Org. Chem. 2016, 12, 2556–2562, doi:10.3762/bjoc.12.250

• to use 6-azido-3-deazapurine ribonucleoside as key intermediate Our initial attempts to create an efficient route to c3A started with the smooth transformation of commercially available 4-chloroimidazo[4,5-c]pyridine with lithium azide to provide 4-azidoimidazo[4,5-c]pyridine (1) [27] (Scheme 3

Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins

• Laszlo Jicsinszky,
• Marina Caporaso,
• Katia Martina,
• Emanuela Calcio Gaudino and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2016, 12, 2364–2371, doi:10.3762/bjoc.12.230

• friendly procedures. Ball mill assisted syntheses are good alternatives to overcome solubility difficulties in syntheses or isolation of natural compounds from vegetables using CDs [9][10]. Environmentally benign synthetic methods of CD derivatives have been recently reviewed [11]. The key intermediate in

Enduracididine, a rare amino acid component of peptide antibiotics: Natural products and synthesis

• Darcy J. Atkinson,
• Briar J. Naysmith,
• Daniel P. Furkert and
• Margaret A. Brimble

Beilstein J. Org. Chem. 2016, 12, 2325–2342, doi:10.3762/bjoc.12.226

• afforded the free amino acid in four steps via key intermediate 4-hydroxyarginine 62. The synthesis of nitro alcohol 61 was not described but its preparation has been reported [65]. All four diastereomers were synthesised for comparison with the isolated enduracididine sample. Synthesis of L-allo

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• donors via chain extension catenation of alkylthiophenes. We have used commercially available 3-butyl-, 3-hexyl- and 3-octylthiophene to form the key intermediate TMS-alkylthiophene boronic acid pinacol esters (3) in high yield on a large scale and in high purity as they can be purified by distillation

A new and expeditious synthesis of all enantiomerically pure stereoisomers of rosaprostol, an antiulcer drug

• Wiesława Perlikowska,
• Remigiusz Żurawiński and
• Marian Mikołajczyk

Beilstein J. Org. Chem. 2016, 12, 2234–2239, doi:10.3762/bjoc.12.215

• methanephosphonate into (±)-1 was achieved in only seven steps and in 42% overall yield. Racemic 2-dimethoxyphosphoryl-3-hexylcyclopentan-1-one (3) is the key intermediate in this synthesis. This report describes the resolution of (±)-3 into its enantiomers and their application as starting chiral reagents for the

The direct oxidative diene cyclization and related reactions in natural product synthesis

• Juliane Adrian,
• Leona J. Gross and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2016, 12, 2104–2123, doi:10.3762/bjoc.12.200

• in Scheme 3). The key intermediate and cyclization precursor may then involve a coordinative bond of that ether oxygen to the strongly Lewis acidic metal center. Due to the close relation to type B cyclizations, they can be classified as type B’ (Scheme 3). Reagents that mediate this type of reaction

• was intramolecularly trapped by attack of the remote hydroxy group to afford bis-THF 54, a key intermediate en route to membranacin (55) (Scheme 12) [102]. One year later, in 2005, Brown and co-workers achieved a total synthesis of 21,22-diepi-membrarollin (60) [105], possessing an adjacent bis-THF

• an oxidative cyclization using stoichiometric amounts of sodium permanganate to furnish trans-THF diol 78 in 73% yield with an excellent diastereomeric ratio of 97:3 induced by a cyclohexanol derived chiral auxiliary. This key intermediate was subsequently converted to natural trans-(+)-linalool

Beta-hydroxyphosphonate ribonucleoside analogues derived from 4-substituted-1,2,3-triazoles as IMP/GMP mimics: synthesis and biological evaluation

• Tai Nguyen Van,
• Audrey Hospital,
• Corinne Lionne,
• Lars P. Jordheim,
• Charles Dumontet,
• Christian Périgaud,
• Laurent Chaloin and
• Suzanne Peyrottes

Beilstein J. Org. Chem. 2016, 12, 1476–1486, doi:10.3762/bjoc.12.144

• synthesis of 1,2,3-triazolonucleotides (1a–o, Figure 1) was envisaged using the Huisgen 1,3-dipolar cycloaddition of the azido-sugar-phosphonate key-intermediate 2 (Scheme 1) and selected commercially available alkynes. Thus, (1-azido-2,5-di-O-acetyl-3-O-benzoyl-6-deoxy-6-diethylphosphono)-β-ribo-(5S

Synthesis of ferrocenyl-substituted 1,3-dithiolanes via [3 + 2]-cycloadditions of ferrocenyl hetaryl thioketones with thiocarbonyl S-methanides

• Grzegorz Mlostoń,
• Róża Hamera-Fałdyga,
• Anthony Linden and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2016, 12, 1421–1427, doi:10.3762/bjoc.12.136

• 1,5-diradical as a key intermediate. The complete change of the reaction mechanism toward the concerted [3 + 2]-cycloaddition was observed in the reaction of a sterically crowded cycloaliphatic thiocarbonyl ylide with ferrocenyl methyl thioketone. Keywords: [3 + 2]-cycloadditions; 1,3-dithiolanes

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• ’-position of the BINOL backbone had a remarkable effect on the catalytic activity and enantioselectivity. Based on this method, the authors also achieved the synthesis of a key intermediate efficiently (99% yield and 93% ee), which had been used in the total synthesis of (+)-folicanthine [68]. The Zhang

A robust synthesis of 7,8-didemethyl-8-hydroxy-5-deazariboflavin

• Matthias Bender,
• Henrik Mouritsen and
• Jens Christoffers

Beilstein J. Org. Chem. 2016, 12, 912–917, doi:10.3762/bjoc.12.89

• transformed to the corresponding protected ribitylamine via the oxime, which was submitted to reduction with LiAlH4. Key advantage compared to previous syntheses is the utilization of a polyol-protective group which allowed the chromatographic purification of a key-intermediate product providing the target

• biosynthetic precursor compound to cofactor F420. In comparison with older routes to this target compound, the key innovation of our procedures is the introduction of two isopropylidene protective groups into the ribose side chain, which allowed the chromatographic purification of key intermediate product 11