Vicinal difluorination as a C=C surrogate: an analog of piperine with enhanced solubility, photostability, and acetylcholinesterase inhibitory activity

• Yuvixza Lizarme-Salas,
• Alexandra Daryl Ariawan,
• Ranjala Ratnayake,
• Hendrik Luesch,
• Angela Finch and
• Luke Hunter

Beilstein J. Org. Chem. 2020, 16, 2663–2670, doi:10.3762/bjoc.16.216

• for E-alkenes in medicinal chemistry. Keywords: Alzheimer's disease; bioisostere; conformational analysis; gauche effect; stereoselective synthesis; Introduction Piperine (1, Figure 1) is a well-known natural product that is derived from peppercorns [1][2][3]. Many biological studies of 1 have been

Synthesis of the tetrasaccharide repeating unit of the O-specific polysaccharide of Azospirillum doebereinerae type strain GSF71^T using linear and one-pot iterative glycosylations

• Arin Gucchait,
• Pradip Shit and
• Anup Kumar Misra

Beilstein J. Org. Chem. 2020, 16, 1700–1705, doi:10.3762/bjoc.16.141

• synthetic intermediates. Stepwise stereoselective synthesis of tetrasaccharide 1. Reagents and conditions: (a) NIS, HClO4-SiO2, CH2Cl2, MS 4 Å, −15 °C, 30 min, then 20 °C, 30 min, 73% for compound 5, 70% for compound 6, and 74% for compound 7; (b) CH3COSH, pyridine, rt, 16 h; (c) HClO4-SiO2, CH3CN, rt, 15

An overview on disulfide-catalyzed and -cocatalyzed photoreactions

• Yeersen Patehebieke

Beilstein J. Org. Chem. 2020, 16, 1418–1435, doi:10.3762/bjoc.16.118

• . In 1996, Burton and co-workers reported the stereoselective synthesis of cis-1,2-difluorotriethylsilyethylene and its conversion to a variety of cis-1,2-difluoroethylene synthons, which are important building blocks in the preparation of fluorine-containing pharmaceuticals, polymers, and bioactive

Distinctive reactivity of N-benzylidene-[1,1'-biphenyl]-2-amines under photoredox conditions

• Shrikant D. Tambe,
• Kwan Hong Min,
• Naeem Iqbal and
• Eun Jin Cho

Beilstein J. Org. Chem. 2020, 16, 1335–1342, doi:10.3762/bjoc.16.114

• . The developed method can be employed for the synthesis of various bulky vicinal diamines, which are potential ligands in stereoselective synthesis. Keywords: 1,2-diamine; diversity; imine; photocatalysis; visible light; Introduction The selective formation of distinct valuable compounds from the

• heterocoupling with aliphatic amines. Furthermore, the reduced amine product was also obtained by employing the Hantzsch ester. The developed method can be employed for the synthesis of bulky vicinal diamines with potential applications as ligands for stereoselective synthesis. Experimental An oven-dried

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• Chemistry Centre, Departament of Chemistry, Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Str. Arany Janos 11, RO-400028 Cluj−Napoca, Romania 10.3762/bjoc.16.98 Abstract The stereoselective synthesis of truxillic bis-amino esters from polyfunctional oxazolones is reported. The

Palladium-catalyzed regio- and stereoselective synthesis of aryl and 3-indolyl-substituted 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones

• Valeria Nori,
• Antonio Arcadi,
• Armando Carlone,
• Fabio Marinelli and
• Marco Chiarini

Beilstein J. Org. Chem. 2020, 16, 1084–1091, doi:10.3762/bjoc.16.95

• (Te), Italy 10.3762/bjoc.16.95 Abstract Cascade cyclocarbopalladation of the readily available aryl/alkyl-substituted propargylic amides containing an aryl iodide moiety, followed by Suzuki–Miyaura coupling with arylboronic acids, allowed an efficient regio- and stereoselective synthesis of

• functionalized alkynes with boronic acids [32][33] prompted us to explore the palladium-catalyzed reaction of the readily available alkynyliodobenzamides 2 with boronic acids 3 as a viable route to the regio- and stereoselective synthesis of 4-alkylidene-3,4-dihydroisoquinolin-1(2H)-ones 3 (Scheme 1a). We are

• presence of a catalytic amount of the ligand-free PdCl2 in environmentally friendly ethanol, achieve an efficient regio- and stereoselective synthesis of 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones 4. It is worth noting that, during the preparation of this paper, a related article focused on the

Combining enyne metathesis with long-established organic transformations: a powerful strategy for the sustainable synthesis of bioactive molecules

• Valerian Dragutan,
• Ileana Dragutan,
• Albert Demonceau and
• Lionel Delaude

Beilstein J. Org. Chem. 2020, 16, 738–755, doi:10.3762/bjoc.16.68

• subsequent Eu(fod)3-catalyzed intermolecular Diels–Alder cycloaddition and epoxidation reactions (Scheme 5) [69]. In this stereoselective synthesis, the last biomimetic step was critical to obtain the proper enantiomer of the tetracyclic core of nanolobatolide. Amphidinolide macrolides Amphidinolides

• enantiopure trienyne or diene–diyne metathesis precursors were readily obtained from (S)-citronellal by a highly diastereoselective organocatalytic Michael addition. Erogorgiaene An exceptionally stereoselective synthesis of erogorgiaene (12) (95% E-selectivity) was reported by Hoveyda et al. [80]. They

• subunit, including Diels–Alder cycloaddition and advanced functionalization reactions, gave access to manzamine A and E. Rhodexin A Jung et al. [87][88][89] succeeded in the stereoselective synthesis of rhodexin A (17), a steroid with potent cardiotonic properties and with activity against human leukemia

Towards the total synthesis of chondrochloren A: synthesis of the (Z)-enamide fragment

• Jan Geldsetzer and
• Markus Kalesse

Beilstein J. Org. Chem. 2020, 16, 670–673, doi:10.3762/bjoc.16.64

• Hannover, Germany 10.3762/bjoc.16.64 Abstract The stereoselective synthesis of the (Z)-enamide fragment of chondrochloren (1) is described. A Buchwald-type coupling between amide 3 and (Z)-bromide 4 was used to generate the required fragment. The employed amide 3 comprising three chiral centers was

Synthesis of disparlure and monachalure enantiomers from 2,3-butanediacetals

• Adam Drop,
• Hubert Wojtasek and
• Bożena Frąckowiak-Wojtasek

Beilstein J. Org. Chem. 2020, 16, 616–620, doi:10.3762/bjoc.16.57

• Adam Drop Hubert Wojtasek Bozena Frackowiak-Wojtasek Institute of Chemistry, Opole University, ul. Oleska 48, 45-052 Opole, Poland ZWP EMITOR S.C., ul. Olimpijska 6, 45-681 Opole, Poland 10.3762/bjoc.16.57 Abstract 2,3-Butanediacetal derivatives were used for the stereoselective synthesis of

Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

• Svetlana V. Amosova,
• Andrey A. Filippov,
• Nataliya A. Makhaeva,
• Alexander I. Albanov and
• Vladimir A. Potapov

Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47

• -thiaselenole; nucleophilic addition; nucleophilic substitution; rearrangement; seleniranium intermediate; Introduction The regio- and stereoselective synthesis of organoselenium compounds based on selenium-centered electrophilic reagents has been one of the most important and effective directions in

• did not occur (Scheme 2). The high anchimeric assistance effect of the selenium atom in thiaselenole 1 is the driving force for the generation of the seleniranium intermediate 2. A fundamental approach to the regio- and stereoselective synthesis of unsaturated functionalized organoselenium compounds

• temperature underwent rearrangement and ring contraction to 1,3-thiaselenol-2-ylmethyl selenocyanate 4. These rearrangements proceeded via a seleniranium cation 2 that is attacked by the nucleophilic selenocyanate anion at two different carbon atoms of the three-membered ring. The regio- and stereoselective

Architecture and synthesis of P,N-heterocyclic phosphine ligands

• Wisdom A. Munzeiwa,
• Bernard Omondi and
• Vincent O. Nyamori

Beilstein J. Org. Chem. 2020, 16, 362–383, doi:10.3762/bjoc.16.35

• steric properties, use of low-priced and easily available reagents, mild and expedient reaction conditions, and few reaction steps. The motifs can also be chiral, and this is helpful in stereoselective synthesis. The introduction of different moieties can bring about enhanced properties like fluorescence

A review of asymmetric synthetic organic electrochemistry and electrocatalysis: concepts, applications, recent developments and future directions

• Munmun Ghosh,
• Valmik S. Shinde and
• Magnus Rueping

Beilstein J. Org. Chem. 2019, 15, 2710–2746, doi:10.3762/bjoc.15.264

• 2007, Feroci disclosed an electrochemical strategy for the cis-stereoselective synthesis of chiral β-lactams 180 via a 4-exo-tet cyclization of bromo amides 178 with an acidic methylene group and bearing a chiral auxiliary [101]. The cyclization occurred via deprotonation of the acidic methylene group

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

• peptidyl nucleosides with primarily antifungal properties. The stereoselective synthesis of (+)-polyoxamic acid ((2S,3S,4S)-144) was successfully carried out starting with Horner–Wadsworth–Emmons olefination of the aziridine aldehyde (2R,1'R)-6 which provided a 98:2 mixture of trans- and cis-acrylates 69b

Robust perfluorophenylboronic acid-catalyzed stereoselective synthesis of 2,3-unsaturated O-, C-, N- and S-linked glycosides

• Madhu Babu Tatina,
• Xia Mengxin,
• Rao Peilin and
• Zaher M. A. Judeh

Beilstein J. Org. Chem. 2019, 15, 1275–1280, doi:10.3762/bjoc.15.125

Synthesis of the polyketide section of seragamide A and related cyclodepsipeptides via Negishi cross coupling

• Jan Hendrik Lang and
• Thomas Lindel

Beilstein J. Org. Chem. 2019, 15, 577–583, doi:10.3762/bjoc.15.53

• assembled by solution-phase synthesis and an open-chain analogue of the natural product was obtained. Keywords: jasplakinolide; marine natural products; Negishi coupling; polyketides; stereoselective synthesis; Introduction Our program on the synthesis of biologically active natural products with peptide

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

• -ribofuranose (2a) for the synthesis of β-NR+Br−. 2.1.2. Glycosylation with 1,2,3,5-tetra-O-acyl-ribofuranoses by the silyl-Hilbert–Johnson method: Further developments in a more efficient and stereoselective synthesis of NR+ salt forms were achieved by the application of the silyl-Hilbert–Johnson method based

Sigmatropic rearrangements of cyclopropenylcarbinol derivatives. Access to diversely substituted alkylidenecyclopropanes

• Guillaume Ernouf,
• Jean-Louis Brayer,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2019, 15, 333–350, doi:10.3762/bjoc.15.29

• compounds 78 (98%) and 79 (99%), and to the azabicyclic product 80 (45%), respectively, with high diastereoselectivities (Scheme 27) [61][65]. Conclusion In recent years, [2,3]- and [3,3]-sigmatropic rearrangements of cyclopropenylcarbinol derivatives have emerged as useful tools for the stereoselective

• synthesis of a wide variety of alkylidenecyclopropanes, substituted by heteroatoms (P, O, N, F) and/or incorporating valuable functional groups (α-alkoxy or α-amino acid derivatives) which are potentially useful for further functionalization. The reactivity of heterosubstituted/functionalized

Application of olefin metathesis in the synthesis of functionalized polyhedral oligomeric silsesquioxanes (POSS) and POSS-containing polymeric materials

• Patrycja Żak and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2019, 15, 310–332, doi:10.3762/bjoc.15.28

• the application of ADMET in the synthesis of oligomers or polymers containing a POSS unit in the main chain. Marciniec disclosed ADMET copolymerization of DDSQ-2SiVi with dienes in the stereoselective synthesis of a new class of vinylene–arylene copolymers containing double-decker silsesquioxanes in

Green synthesis of new chiral 1-(arylamino)imidazo[2,1-a]isoindole-2,5-diones from the corresponding α-amino acid arylhydrazides in aqueous medium

• Nadia Bouzayani,
• Jamil Kraїem,
• Sylvain Marque,
• Yakdhane Kacem,
• Abel Carlin-Sinclair,
• Jérôme Marrot and
• Béchir Ben Hassine

Beilstein J. Org. Chem. 2018, 14, 2923–2930, doi:10.3762/bjoc.14.271

• have been known as an important herbicides for bud growth inhibition [2][3][4][5][6] and plant growth regulation [7][8][9][10][11]. Several research groups have turned to the synthesis of these structural analogues (Figure 1) [12]. For example, the stereoselective synthesis of chiral 1H-imidazo[2,1-a

Some mechanistic aspects regarding the Suzuki–Miyaura reaction between selected ortho-substituted phenylboronic acids and 3,4,5-tribromo-2,6-dimethylpyridine

• Piotr Pomarański,
• Piotr Roszkowski,
• Jan K. Maurin,
• Armand Budzianowski and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2018, 14, 2384–2393, doi:10.3762/bjoc.14.214

• transformation [22]. In such cases the stereoselectivity may depend on additional chelation effects [28][29][30][31][32][33][34]. Buchwald and co-workers reported an efficient stereoselective synthesis of axially chiral biarylamides by Pd–O bond formation during the oxidative addition step [28][29]. Also other

• less thermodynamically stable isomer, e.g., (syn)-7. In the reaction with ortho-chlorophenylboronic acid, however, the metal chelation is not present and consequently, the thermodynamic product anti-15 is preferentially formed. This observation may be useful in the design of the stereoselective

• synthesis of polyarylated systems. All obtained ortho-methoxy-substituted derivatives of pyridine 2 and 6–9 as well as ortho-chloro-substituted pyridine derivatives 13, 15–17 are chiral molecules and therefore a method for enantiomer discrimination was needed, especially in the case of the planned

Stereoselective total synthesis and structural revision of the diacetylenic diol natural products strongylodiols H and I

• Pamarthi Gangadhar,
• Sayini Ramakrishna,
• Ponneri Venkateswarlu and
• Pabbaraja Srihari

Beilstein J. Org. Chem. 2018, 14, 2313–2320, doi:10.3762/bjoc.14.206

• ) Red-Al, anh. Et2O, −20 °C, 8 h, 95%; (c) (i) DMSO, CH2Cl2, (COCl)2, −78 °C, (ii) TMS-C≡CH, n-BuLi, THF, −78 °C to rt, 3 h, 89%; (d) K2CO3, MeOH, 0 °C to rt, 1 h, 92%; (e) TBSCl, imidazole, 0 °C to rt, 1 h, 98%; (f) I2, TPP, imidazole, 0 °C to rt, 1 h, 92%. Stereoselective synthesis of (R)-25. Reagents

D-Fructose-based spiro-fused PHOX ligands: synthesis and application in enantioselective allylic alkylation

• Michael R. Imrich,
• Jochen Kraft,
• Cäcilia Maichle-Mössmer and
• Thomas Ziegler

Beilstein J. Org. Chem. 2018, 14, 2082–2089, doi:10.3762/bjoc.14.182

• enantioselectivity [1][2]. Probably the most effective approach in stereoselective synthesis is enantioselective catalysis, because cheap prochiral starting materials can be converted into chiral enantiopure products and no undesirable side products are formed [3][4]. Therefore, the development of new ligands is

• crucial for further progress in stereoselective synthesis [5]. Privileged ligands often used are phosphinooxazoline ligands (PHOX ligands 1, (Figure 1)) which were developed in 1993 independently by Helmchen, Pfaltz and Williams [6][7][8]. Palladium– and iridium–PHOX complexes were already applied as

• efficient catalysts in various asymmetric reactions, for instance allylic substitution and enantioselective hydrogenation [9]. They were also applied in the stereoselective synthesis of complex natural products [10][11][12]. PHOX ligands are nonsymmetrical ligands which can coordinate to a metal center

Recent advances in hypervalent iodine(III)-catalyzed functionalization of alkenes

• Xiang Li,
• Pinhong Chen and
• Guosheng Liu

Beilstein J. Org. Chem. 2018, 14, 1813–1825, doi:10.3762/bjoc.14.154

• high yields [61]. Recently, Jacobsen and co-workers reported the stereoselective synthesis of syn-β-fluoroaziridine building blocks via a chiral aryl iodide-catalyzed fluorination of allylic amines (Scheme 11) [62]. On the basis of their previous work, the C2-symmetric aryl iodide 31 as a catalyst was

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

• Fateh V. Singh,
• Priyanka B. Kole,
• Saeesh R. Mangaonkar and
• Samata E. Shetgaonkar

Beilstein J. Org. Chem. 2018, 14, 1778–1805, doi:10.3762/bjoc.14.152

• stereoselective synthesis. Additionally, the applications of these reagents in natural product synthesis are also covered. Keywords: hypervalent iodine reagents; iodoarenes; natural products; oxidative cyclization; spirocyclic compounds; Review 1. Introduction The chemistry of spirocyclic compounds is a well

• slow when 10 mol % of additive was used. Once again, iodine(III) species was generated in situ which was probably working as active catalytic species. 2.3. Stereoselective synthesis of spirolactones Recently, Kita and co-workers [78] reported a new type of binaphthyl-based chiral iodine(III) species 38

• ). It was noted that mCPBA/TFA combination did not work well for some transformations and it was replaced with oxidant urea·H2O2 and TFAA as an additive. 3.3. Stereoselective synthesis of spirolactams Gong and co-workers [102] efficiently cyclized 1-hydroxy-N-aryl-2-naphthamides 84 to corresponding

Glycosylation reactions mediated by hypervalent iodine: application to the synthesis of nucleosides and carbohydrates

• Yuichi Yoshimura,
• Hideaki Wakamatsu,
• Yoshihiro Natori,
• Yukako Saito and
• Noriaki Minakawa

Beilstein J. Org. Chem. 2018, 14, 1595–1618, doi:10.3762/bjoc.14.137

• oxidative glycosylation reaction to stereoselectively give C2-acyloxylated β-glycosides in good yields [84] (Scheme 22). Hotha and co-workers utilized the reaction of glycals with hypervalent iodine reagents for the stereoselective synthesis of C2 deoxyglycosides and amino acid glycoconjugates [85]. In