Syntheses of spliceostatins and thailanstatins: a review

• William A. Donaldson

Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166

• segment of FR901464 (1) via asymmetric catalysis Similar to their preparation of the C-8–C-15 segment, Jacobsen’s group relied on a Cr(III)-catalyzed silyloxydiene/aldehyde cycloaddition for the C-1–C-7 segment (Scheme 14) [17][18]. The reaction of the protected glycolaldehyde 86 with (1E,3E)-2

Pd-catalyzed asymmetric Suzuki–Miyaura coupling reactions for the synthesis of chiral biaryl compounds with a large steric substituent at the 2-position

• Yongsu Li,
• Bendu Pan,
• Xuefeng He,
• Wang Xia,
• Yaqi Zhang,
• Hao Liang,
• Chitreddy V. Subba Reddy,
• Rihui Cao and
• Liqin Qiu

Beilstein J. Org. Chem. 2020, 16, 966–973, doi:10.3762/bjoc.16.85

• bromobenzene substrates and the Pd···O interaction between carbonyl and palladium seem essential to achieve high enantioselectivity. Keywords: asymmetric catalysis; biaryls; monophosphine ligand; palladium catalyst; Suzuki–Miyaura couplings; Introduction Axially chiral molecules have received much attention

• from chemists because of their widespread appearance in biologically active compounds [1][2][3][4] such as vancomycin [5] and korupensamine A [6] and as useful chiral ligands in asymmetric catalysis. Different strategies with various metals and phosphine ligands had been successfully employed for the

Synthesis of triphenylene-fused phosphole oxides via C–H functionalizations

• Md. Shafiqur Rahman and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2020, 16, 524–529, doi:10.3762/bjoc.16.48

• extended π-system. These included, in particular, those fused with polycyclic aromatic hydrocarbons (PAHs) for possible applications in organic electronics, bioimaging and sensing, and asymmetric catalysis (Figure 1). To name a few examples, Yamaguchi et al. described synthetic routes to novel phosphorus

• -containing ladder molecules and their application as fluorescence probes for biological imaging [10][11]. Marinetti extensively studied the synthesis of phosphahelicenes with linear fusion of the phosphole and the carbohelicene units [12], and their applications in asymmetric catalysis [13] and organic light

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

• -naphthyl)phosphines [R = 2-(2-pyridyl) and 2-(2-pyrazinyl] (QUINAP) by Brown et al. [88] as ligands for asymmetric catalysis instigated the synthesis of structurally similar ligands. Flanagan et al. [89] modified the QUINAP ligand by attaching 2-(2-pyridyl) (R = CH) and 2-(2-pyrazinyl) (R = N) moieties on

• family of privileged chiral ligands in asymmetric catalysis [12]. In these compounds, the C2 axis of symmetry helps in increasing the selectivity of the formation of certain enantiomers by inhibiting other possible reaction pathways [93]. In particular, biarylphosphines and bidentate 2,2'-bis

• dimethylamine or, by using ferrocenyl(dimethylamino)acetonitrile. The phosphine group is introduced by ortho-lithiation of the ferrocenylamine followed by subsequent trapping with chlorophosphine [114][115]. Preceding the ground breaking work by Pfaltz, many P,N ligands have been prepared for asymmetric

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

• . Thus, more economical and ecological alternatives need to be examined, in particular if larger scale production is envisaged. Regarding stereochemical induction, the design of chiral media, similar to chiral solvents in asymmetric catalysis, is still limited. While the chemical modification of

Attempted synthesis of a meta-metalated calix[4]arene

• Christopher D. Jurisch and
• Gareth E. Arnott

Beilstein J. Org. Chem. 2019, 15, 1996–2002, doi:10.3762/bjoc.15.195

• potential implications for asymmetric catalysis, due to the inherent chirality of the calix[4]arene, coupled with the point chirality from, for example, a tetrahedral ruthenium center. We therefore decided to apply the methods reported by Albrecht to a calix[4]arene system in order to prove this theory

Enantioselective Diels–Alder reaction of anthracene by chiral tritylium catalysis

• Qichao Zhang,
• Jian Lv and
• Sanzhong Luo

Beilstein J. Org. Chem. 2019, 15, 1304–1312, doi:10.3762/bjoc.15.129

• presence of strong Lewis acids [36]. We herein report the design and exploration of a new trityl carbocation that has a chiral weakly coordinating Fe(III)-based phosphate anion for the effective asymmetric catalysis in the Diels–Alder reaction of anthracenes. Results and Discussion In our previous work, we

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

• Alexander N. Reznikov,
• Anastasiya E. Sibiryakova,
• Marat R. Baimuratov,
• Eugene V. Golovin,
• Victor B. Rybakov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127

• catalytic Michael reaction itself was carried out with high diastereoselectivity, but the Michael adducts may epimerize at the C-2 position at a significant rate. Conditions for the preparation of individual diastereomers were found. Keywords: asymmetric catalysis; chiral diamine ligands; ketosulfones

Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

• Alexander F. de la Torre,
• Gabriel S. Scatena,
• Oscar Valdés,
• Daniel G. Rivera and
• Márcio W. Paixão

Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118

• ; multicomponent reactions; organocatalysis; polyfurfuryl alcohol; Introduction The immobilization of secondary amine-based catalysts onto organic polymers and silica gel has emerged as an effective strategy that combines the power of heterogeneous and organocatalysis [1][2][3]. Asymmetric catalysis using polymer

Homo- and hetero-difunctionalized β-cyclodextrins: Short direct synthesis in gram scale and analysis of regiochemistry

• Gábor Benkovics,
• Mihály Bálint,
• Éva Fenyvesi,
• Erzsébet Varga,
• Szabolcs Béni,
• Konstantina Yannakopoulou and
• Milo Malanga

Beilstein J. Org. Chem. 2019, 15, 710–720, doi:10.3762/bjoc.15.66

• based on stereoselective interactions of CDs with guest molecules (chiral separations, asymmetric catalysis, enzyme mimics) [20]. However, if the target is only the side-selectivity of difunctionalization, pseudoenantiomeric mixtures of the regioisomers can be used [21]. For CD-based multifunctional

The LANCA three-component reaction to highly substituted β-ketoenamides – versatile intermediates for the synthesis of functionalized pyridine, pyrimidine, oxazole and quinoxaline derivatives

• Tilman Lechel,
• Roopender Kumar,
• Mrinal K. Bera,
• Reinhold Zimmer and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2019, 15, 655–678, doi:10.3762/bjoc.15.61

• chiral compounds were converted into the corresponding pyridin-4-ol derivatives and tested as chiral ligands in asymmetric catalysis [37]. Using the N-trityl-substituted proline as carboxylic acid provided the expected β-ketoenamide KE42 in low yield and as major product we isolated compound 7 in 49

Asymmetric synthesis of a high added value chiral amine using immobilized ω-transaminases

• Antonella Petri,
• Valeria Colonna and
• Oreste Piccolo

Beilstein J. Org. Chem. 2019, 15, 60–66, doi:10.3762/bjoc.15.6

• sustainable approach to an industrial scale. Keywords: asymmetric catalysis; biotransformations; chiral amine; immobilized enzymes; ω-transaminases; Introduction Enantiomerically pure amines are important precursors to biologically active compounds with different industrial applications, including

A novel and practical asymmetric synthesis of eptazocine hydrobromide

• Ruipeng Li,
• Zhenren Liu,
• Liang Chen,
• Jing Pan,
• Kuaile Lin and
• Weicheng Zhou

Beilstein J. Org. Chem. 2018, 14, 2340–2347, doi:10.3762/bjoc.14.209

• were optimized to obtain the product in excellent overall yield and purity. Keywords: alkylation; asymmetric catalysis; eptazocine; Mannich cyclization; Introduction Eptazocine hydrobromide (1, Scheme 1), (1S,6S)-1,4-dimethyl-2,3,4,5,6,7-hexahydro-1H-1,6-methanobenzo[e]azonine-10-ol hydrobromide

• and methallyl iodide [10]. However, these methods were undermined by expensive reagents, poor yields, harsh reaction conditions, or complex synthetic procedures. Phase-transfer asymmetric catalysis using cinchona alkaloid-derived quaternary ammonium salts is a practical method in organic synthesis [11

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

• .14.182 Abstract Phosphinooxazoline (PHOX) ligands are an important class of ligands in asymmetric catalysis. We synthesized ten novel D-fructose-derived spiro-fused PHOX ligands with different steric and electronic demand. The application of two of them was tested in asymmetric allylic alkylation. The

• strongly decreased with longer reaction times (see Supporting Information File 1 for details). With the fructose-based spiro-fused PHOX ligands in hand, we turned to some preliminary tests in order to evaluate the usefulness of our ligands in asymmetric catalysis. We chose to test one ligand with ether

• lead to the highest er in our preliminary tests. The reason for this will to be studied in further investigations, as well as the application of other spiro-fused PHOX ligands in asymmetric catalysis. Conclusion In conclusion, we developed a short and efficient synthesis for D-fructose-based spiro

Synthesis and supramolecular self-assembly of glutamic acid-based squaramides

• Juan V. Alegre-Requena,
• Marleen Häring,
• Isaac G. Sonsona,
• Alex Abramov,
• Eugenia Marqués-López,
• Raquel P. Herrera and
• David Díaz Díaz

Beilstein J. Org. Chem. 2018, 14, 2065–2073, doi:10.3762/bjoc.14.180

• asymmetric catalysis and molecular recognition [5][6]. Besides, squaramides present a dual ability to recognize anions and cations through hydrogen bonding interactions, acting as ion sensors and transmembrane anion transporters [7]. This property has been crucial for the development of new drugs [8][9

Chiral bisoxazoline ligands designed to stabilize bimetallic complexes

• Deepankar Das,
• Rudrajit Mal,
• Nisha Mittal,
• Zhengbo Zhu,
• Thomas J. Emge and
• Daniel Seidel

Beilstein J. Org. Chem. 2018, 14, 2002–2011, doi:10.3762/bjoc.14.175

• pyridazine-bridged, and bis-nickel as well as bis-palladium pyrazole-bridged complexes were obtained. Keywords: bimetallic complexes; bisoxazolines; chiral ligands; heterocycles; Introduction Metal-centered asymmetric catalysis most commonly relies on monometallic complexes of various chiral ligands, among

• monooxygenase [10], ribonucleotide reductase [11], catechol oxidase [12], and arginase [13], are prominent examples of such bimetallic enzymes. A range of bi- and multi-metallic complexes have been utilized in asymmetric catalysis (Figure 1) [6]. For instance, Shibasaki and co-workers introduced a number of

• the development of new catalytic enantioselective transformations. Examples of chiral bimetallic complexes utilized in asymmetric catalysis. Previously reported bisoxazoline ligands capable of stabilizing bimetallic complexes. Thermal ellipsoid plot (50% probability) of the molecular structure of 16

Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives

• Zheng-Yi Li,
• Hong-Xiao Tong,
• Yuan Chen,
• Hong-Kui Su,
• Tangxin Xiao,
• Xiao-Qiang Sun and
• Leyong Wang

Beilstein J. Org. Chem. 2018, 14, 1901–1907, doi:10.3762/bjoc.14.164

• reactions in aqueous solution with excellent enantioselectivity [35]. As part of our ongoing studies to develop novel types of organocatalysts for asymmetric catalysis, in this study, we aimed to synthesize novel upper rim-functionalized calix[4]thiourea cyclohexanediamine derivatives to catalyze asymmetric

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

• hypervalent iodine(III)-catalyzed functionalization of alkenes and asymmetric reactions using a chiral iodoarene are summarized. Keywords: asymmetric catalysis; functionalization of alkenes; hypervalent iodine(III); Introduction Hypervalent iodine(III) reagents, also named as λ3-iodanes, have been widely

Enantioselective phase-transfer catalyzed alkylation of 1-methyl-7-methoxy-2-tetralone: an effective route to dezocine

• Ruipeng Li,
• Zhenren Liu,
• Liang Chen,
• Jing Pan and
• Weicheng Zhou

Beilstein J. Org. Chem. 2018, 14, 1421–1427, doi:10.3762/bjoc.14.119

• -dibromopentane, and the best catalyst (C7) was identified. In addition, optimizations of the alkylation were carried out so that the process became practical and effective. Keywords: alkylation; asymmetric catalysis; cinchonidine; dezocine; Introduction The preparation of enantiomerically pure compounds has

• become a stringent requirement for pharmaceutical synthesis [1]. In this context, asymmetric catalysis is probably one of the most attractive procedures for the synthesis of active pharmaceutical ingredients (APIs) due to environmental, operational, and economic benefits. Dezocine, (5R,11S,13S)-13-amino

• separated by two times of resolution with L-tartaric acid and D-tartaric acid (Scheme 1). Phase-transfer asymmetric catalysis with cinchona alkaloid-derived quaternary ammonium compounds has become one of the topics in stereoselective synthesis in both industry and academia [6][7][8][9]. It was reported [10

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• Analysis Technological Application and Research Center (UBATAM), Usak University, Usak, Turkey Vocational School of Health Services, Usak University, 64200 Usak, Turkey 10.3762/bjoc.14.117 Abstract The use of calixarenes in asymmetric catalysis is receiving increasing attention due to their tunable three

• -dimensional molecular platforms along with their easy syntheses and versatile modification at the upper and lower rims. This review summarizes the recent progress of synthesis and use of chiral calixarenes in asymmetric syntheses which emerged later than 2010. Keywords: asymmetric catalysis; chiral

• asymmetric catalysis has received considerable interest and witnessed significant progress in recent years [2][3][4]. Calixarenes are considered as the third generation of supramolecular hosts after cyclodextrins and crown ethers [5][6]. Due to their easy preparation and readily modification at either the

A survey of chiral hypervalent iodine reagents in asymmetric synthesis

• Soumen Ghosh,
• Suman Pradhan and
• Indranil Chatterjee

Beilstein J. Org. Chem. 2018, 14, 1244–1262, doi:10.3762/bjoc.14.107

• of an external oxidant. The use of catalytic chiral hypervalent iodine reagents in asymmetric catalysis is one of the most challenging ongoing topics and this review will focus on the development of various chiral hypervalent iodine reagents and their application in typical organic transformations

An overview of recent advances in duplex DNA recognition by small molecules

• Sayantan Bhaduri,
• Nihar Ranjan and
• Dev P. Arya

Beilstein J. Org. Chem. 2018, 14, 1051–1086, doi:10.3762/bjoc.14.93

• -based asymmetric catalysis by synthesizing various structural analogs of Hoechst 33258. It has been observed that amine analogs (conjugate 53 and 54) showed higher affinity towards ct-DNA and poly[d(A·T)2] in comparison to alkyne analogs with reduced flexibility and one less charged nitrogen atom

Nanoreactors for green catalysis

• M. Teresa De Martino,
• Loai K. E. A. Abdelmohsen,
• Floris P. J. T. Rutjes and
• Jan C. M. van Hest

Beilstein J. Org. Chem. 2018, 14, 716–733, doi:10.3762/bjoc.14.61

• and, thereby, harness its utility for further applications. The abovementioned issues are particularly relevant in the field of asymmetric catalysis, which besides overcoming catalyst compatibility also has to deal with cost issues [11][12]. Research on asymmetric catalysis has been mainly focused on

Investigations towards the stereoselective organocatalyzed Michael addition of dimethyl malonate to a racemic nitroalkene: possible route to the 4-methylpregabalin core structure

• Denisa Vargová,
• Rastislav Baran and
• Radovan Šebesta

Beilstein J. Org. Chem. 2018, 14, 553–559, doi:10.3762/bjoc.14.42

• based on chiral phase-transfer-catalysis of the Michael addition was also reported [26]. In this context, we decided to develop a synthesis of 4-methylpregabalin from a simple and achiral starting material and build its chirality centers using asymmetric catalysis. This paper describes the synthesis of

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 325–344, doi:10.3762/bjoc.14.21

• benzoxathiazine 2,2-dioxides, as electrophiles in the catalytic enantioselective aza-Reformatky reaction [49]. Indeed, these compounds constitute good partners for asymmetric catalysis since they exhibit a rigid structure reducing the conformational mobility and avoiding the E/Z isomerization, thus facilitating