Ligand-dependent stereoselective Suzuki–Miyaura cross-coupling reactions of β-enamido triflates

• Tomáš Chvojka,
• Athanasios Markos,
• Svatava Voltrová,
• Radek Pohl and
• Petr Beier

Beilstein J. Org. Chem. 2021, 17, 2657–2662, doi:10.3762/bjoc.17.179

• isomerization of N-allyl amides [20], but still possess drawbacks, especially for stereoselective synthesis of tri- and tetrasubstituted enamides. Recently, we have reported a triflic acid-mediated reaction of N-fluoroalkyl-1,2,3-triazoles leading to (Z)-β-enamido triflates [21] and Lewis acid-mediated reaction

• configuration of the double bond were formed preferably. Both conditions were applied to a range of arylboronic acids and (Z)-β-enamido triflates. A: Synthesis of (Z)-β-enamido triflates and subsequent stereoselective cross-coupling reactions. B: Ligand-controlled stereoselective synthesis of β,β-diaryl

Solvent-free synthesis of enantioenriched β-silyl nitroalkanes under organocatalytic conditions

• Akhil K. Dubey and
• Raghunath Chowdhury

Beilstein J. Org. Chem. 2021, 17, 2642–2649, doi:10.3762/bjoc.17.177

• Enantioenriched organosilanes are attractive molecules in organic synthesis owing to their potential applications in stereoselective synthesis [1][2]. The unique sterical and electronical features of the C–Si bond can induce stereodifferentiation at the adjacent prostereogenic center in organic transformations [2

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• -Butanesulfinamide is highly useful in stereoselective synthesis as a stereoinducing group [21]. Thus, N-sulfinylureas and thioureas are a new class of organocatalysts, with the sulfinyl group acting both as an acidifying and a chiral controlling moiety. A variety of N-sulfinylureas catalyzed aza-Henry reaction

Recent advances in organocatalytic asymmetric aza-Michael reactions of amines and amides

• Pratibha Sharma,
• Raakhi Gupta and
• Raj K. Bansal

Beilstein J. Org. Chem. 2021, 17, 2585–2610, doi:10.3762/bjoc.17.173

• -MRs, each highlighting a certain aspect of the reaction. While Sánchez-Roselló et al. [18] classified these reactions on the basis of the nature of the substrates, Nayak et al. [19] and Bhanja et al. [20] focused on the stereoselective synthesis of nitrogen heterocycles via Michael cascade reactions

Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds

• Sumana Mandal,
• Raju D. Chaudhari and
• Goutam Biswas

Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153

• . Synthesis of tricyclic heterocyclic scaffolds. HgCl2-mediated cyclization of 2-alkynylphenyl alkyl sulfoxide. a) Hg(OTf)2-catalyzed cyclization of allenes and alkynes. b) Proposed mechanism of cyclization. Stereoselective synthesis of tetrahydropyran derivatives. a) Hg(ClO4)2-catalyzed cyclization of α

Transition-metal-free intramolecular Friedel–Crafts reaction by alkene activation: A method for the synthesis of some novel xanthene derivatives

• Tülay Yıldız,
• İrem Baştaş and
• Hatice Başpınar Küçük

Beilstein J. Org. Chem. 2021, 17, 2203–2208, doi:10.3762/bjoc.17.142

• method using π-activated alcohols has frequently been used for xanthene synthesis. Some of these methods are the stereoselective synthesis of 9-vinyl-substituted unsymmetrical xanthenes and thioxanthenes by intramolecular FCA reaction [39], Lewis acid-catalyzed intramolecular FCA [40], and the synthesis

Progress and challenges in the synthesis of sequence controlled polysaccharides

• Giulio Fittolani,
• Theodore Tyrikos-Ergas,
• Denisa Vargová,
• Manishkumar A. Chaube and
• Martina Delbianco

Beilstein J. Org. Chem. 2021, 17, 1981–2025, doi:10.3762/bjoc.17.129

• considerably reduced the time needed for the stereoselective synthesis of linear α(1–6)-mannans (ranging from 5mer to 20mer) [275]. The biggest advantage of this approach is the easy scalability, up to a gram scale. However, this strategy is limited to one type of linkage (i.e., only α(1–6) linkages) and does

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• determined following a single-crystal X-ray analysis (Scheme 11). The stereoselective synthesis of diastereomeric 2-chloro-2-aroylaziridines 36 and 32 was successfully accomplished through a three-component cascade coupling reaction of silyldichloromethanes 33, arylnitriles 34 and chiral N-tert

• through a cyclic transition state to the Si face of the imine (RS)-14. In this way, both cis-aziridines diastereoisomers 36 and 32 were formed from the same chiral imine 14 and arylnitriles 34 (Scheme 12). Chiral sulfinyl imines have been also used in the stereoselective synthesis of aziridines. The

• pharmacy as highly biological active compounds. Among this group of nitrogenated heterocycles, β-lactams (azetidin-2-ones) have reached especial attention [78][79][80], being easily accessible from β-aminoesters. A stereoselective synthesis of 1-substituted 2-azaspiro[3.3]heptanes 45 (n = 1) was reported

Stereoselective synthesis and transformation of pinane-based 2-amino-1,3-diols

• Ákos Bajtel,
• Mounir Raji,
• Matti Haukka,
• Ferenc Fülöp and
• Zsolt Szakonyi

Beilstein J. Org. Chem. 2021, 17, 983–990, doi:10.3762/bjoc.17.80

• aminohydroxylation process starting from allylic carbamates usually carried out in the presence of potassium osmate [24][25][26][27][28]. In recent years, we have extensively studied the stereoselective synthesis, as well as catalytic and pharmacological applications of monoterpene-based 3-amino-1,2-diols, which are

• oxazolidin-2-one 9. NOESY experiments and X-ray structure proofment of the structure of oxazolidine 17. Proposed pathway for the ring–ring tautomerism. Stereoselective synthesis of the pinane-fused oxazolidin-2-one 9. Stereoselective synthesis of the pinane spiro-fused oxazolidin-2-one 12. Parallel synthesis

Metal-free glycosylation with glycosyl fluorides in liquid SO₂

• Krista Gulbe,
• Jevgeņija Lugiņina,
• Edijs Jansons,
• Artis Kinens and
• Māris Turks

Beilstein J. Org. Chem. 2021, 17, 964–976, doi:10.3762/bjoc.17.78

• facilitating for the synthesis of 2-deoxy glucoside 20 from corresponding fluoride α-19 in 91% yield and good α-selectivity at −10 °C (Scheme 5). Due to the absence of a neighboring group at C2 position, the stereoselective synthesis of 2-deoxy glycosides is challenging [72][73][74]. We hypothesize that the

Prins cyclization-mediated stereoselective synthesis of tetrahydropyrans and dihydropyrans: an inspection of twenty years

• Asha Budakoti,
• Pradip Kumar Mondal,
• Prachi Verma and
• Jagadish Khamrai

Beilstein J. Org. Chem. 2021, 17, 932–963, doi:10.3762/bjoc.17.77

• important building blocks and ubiquitous scaffolds in many natural products and active pharmaceutical ingredients (API). Among various established methods, the Prins reaction has emerged as a powerful technique in the stereoselective synthesis of the tetrahydropyran skeleton with various substituents, and

• metathesis (RCM) [16], halo etherification [17], reductive etherification [18][19], and metal-mediated cyclization [20][21], etc. are the most frequent strategies utilized for THP ring construction (Scheme 1). Amongst all, the Prins reaction has proven as a powerful technique in the stereoselective synthesis

• underwent Prins-type cyclization in the presence of BF3·OEt2 as well as SnBr4 to deliver the desired 37 and 40, respectively, without loss of optical purity (Scheme 9) [34][35]. This strategy was successfully utilized for the synthesis of the natural product (−)-centrolobine [33] and for the stereoselective

Highly regio- and stereoselective phosphinylphosphination of terminal alkynes with tetraphenyldiphosphine monoxide under radical conditions

• Dat Phuc Tran,
• Yuki Sato,
• Yuki Yamamoto,
• Shin-ichi Kawaguchi,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 866–872, doi:10.3762/bjoc.17.72

• Ph2P(O)• as an important species to regioselectively afford 1-phosphinyl-2-phosphinoalkenes. This method can be applied to a wide range of terminal alkynes. We believe that the excellent stereoselectivity to give (E)-isomers is effective for the stereoselective synthesis of (E)-bis(diphenylphosphino

The synthesis of chiral β-naphthyl-β-sulfanyl ketones via enantioselective sulfa-Michael reaction in the presence of a bifunctional cinchona/sulfonamide organocatalyst

• Deniz Tözendemir and
• Cihangir Tanyeli

Beilstein J. Org. Chem. 2021, 17, 494–503, doi:10.3762/bjoc.17.43

• naturally occurring cinchona alkaloids have shown remarkable performance as organocatalysts for stereoselective synthesis in the past decade [1][2][3][4][5][6]. Among them, quinine-derived organocatalysts make a noteworthy appearance in the formation of new stereogenic centres, which can serve as valuable

Diels–Alder reaction of β-fluoro-β-nitrostyrenes with cyclic dienes

• Savva A. Ponomarev,
• Roman V. Larkovich,
• Alexander S. Aldoshin,
• Andrey A. Tabolin,
• Sema L. Ioffe,
• Jonathan Groß,
• Till Opatz and
• Valentine G. Nenajdenko

Beilstein J. Org. Chem. 2021, 17, 283–292, doi:10.3762/bjoc.17.27

• one of the most widely used fluorine-containing building blocks [48][49]. Recently, we have developed an efficient stereoselective synthesis of β-fluoro-β-nitrostyrenes 1 based on the radical nitration of 2-bromo-2-fluorostyrenes [50]. This process takes place with simultaneous elimination of bromine

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

• contradictions regarding the specific rotation values of inthomycin C and securely assigned the (3R)‑configuration for inthomycin C ((−)-3) [57]. In the synthetic studies towards racemic inthomycin C ((rac)-3), Maulide and co-workers investigated the stereoselective synthesis of halocyclobutenes and their ring

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