One-pot synthesis of epoxides from benzyl alcohols and aldehydes

• Edwin Alfonzo,
• Jesse W. L. Mendoza and
• Aaron B. Beeler

Beilstein J. Org. Chem. 2018, 14, 2308–2312, doi:10.3762/bjoc.14.205

• its original disclosure, particular in the area of asymmetric synthesis [22][23][24]. Other notable advancements include the expansion of its scope by using organic bases and a one-pot oxidation/epoxidation sequence of benzyl alcohols with manganese dioxide and an exogenous sulfonium salt [25][26

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

• ][22]. This led us to extend the concept of spiro-fused carbohydrate oxazolines for asymmetric synthesis by developing new types of carbohydrate-based PHOX ligands. Herein, we present ten novel spiro-PHOX ligands containing diphenylphosphino groups, 5, which can be synthesized in four to six steps

β-Hydroxy sulfides and their syntheses

• Mokgethwa B. Marakalala,
• Edwin M. Mmutlane and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1668–1692, doi:10.3762/bjoc.14.143

• reduction of aromatic β-keto sulfides provided excellent enantioselectivity, the reduction of the corresponding alkyl β-keto sulfides gave low enantioselectivity. Ruano and co-workers reported the asymmetric synthesis of β-hydroxy sulfides via connectivity of a suitably substituted benzylic carbanion with

• biocatalysis for the asymmetric synthesis of β-hydroxy sulfides still remains unexplored. 3.1.2 Disulfides as nucleophiles. Whilst thiols are excellent nucleophiles and can open epoxides under a variety of conditions as detailed above, they can be awfully odoriferous and unpleasant to work with [58]. As an

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• investigated and significant achievements have been reported making iodine compounds now useful organocatalysts in asymmetric synthesis (reaction 2 in Scheme 1a) [15][16][17][18][19][20][21][22][23][24]. In parallel to these investigations, a third strategy has been envisaged with the development of tandem

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

• asymmetric synthesis. In 2013, we described a novel class of calix[4]arene-based chiral primary amine–thiourea catalysts 47a and 47b derived from p-tert-butylcalix[4]arene (Figure 7) [49]. To evaluate the catalytic efficiency, bifunctional catalysts were applied to promote the Michael addition of aldehydes

Synthesis of chiral 3-substituted 3-amino-2-oxindoles through enantioselective catalytic nucleophilic additions to isatin imines

• Hélène Pellissier

Beilstein J. Org. Chem. 2018, 14, 1349–1369, doi:10.3762/bjoc.14.114

• imines published since the beginning of 2015. Keywords: asymmetric synthesis; chiral 3-amino-2-oxindoles; chirality; isatin imines; nucleophilic addition; Introduction Chiral oxindoles represent an important class of products widely present in nature and exhibiting many biological activities. Among

• additions to isatin imines have been developed, including Mannich reactions, aza-Morita–Baylis–Hillman reactions, Friedel–Crafts reactions, aza-Henry reactions, additions of heteronucleophiles, Strecker reactions, among others. The goal of this review is to update the catalytic asymmetric synthesis of

• achieved in the past three years in the field of asymmetric synthesis of 3-substituted 3-amino-2-oxindoles through enantioselective nucleophilic additions to isatin imines, involving both chiral metal and organocatalysts. Indeed, a variety of novel methodologies, including enantioselective Mannich

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

• last 25 years. This review highlights the contribution of different chiral hypervalent iodine reagents in diverse asymmetric conversions. Keywords: alkene functionalization; asymmetric synthesis; hypervalent iodine; organocatalysis; oxidation; Introduction It is more than one century ago since the

• ]. They have utilized this chiral difluoroiodonium salt 13 for the asymmetric synthesis of aminofluorinated compounds 66 from 65 (Scheme 14). In addition to this, they extended this methodology for the regioselective intermolecular aminofluorination of styrenes with a racemic catalyst. The nucleophilic

• towards a sustainable replacement of transition metals. The application of chiral hypervalent iodine reagents is expected to pave the way for new reactions and reagent design in the field of asymmetric synthesis and catalysis. An overview of different chiral iodine reagents or precursors thereof

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

A stereoselective and flexible synthesis to access both enantiomers of N-acetylgalactosamine and peracetylated N-acetylidosamine

• Bettina Riedl and
• Walther Schmid

Beilstein J. Org. Chem. 2018, 14, 856–860, doi:10.3762/bjoc.14.71

• : asymmetric synthesis; carbohydrates; N-acetylgalactosamine; N-acetylidosamine; Introduction N-Acetylgalactosamine (GalNAc, Figure 1) and N-acetylidosamine (IdoNAc) belong to the group of 2-amino-2-deoxysugars, which can be found in a wide range of organisms as building blocks of, e.g., glycosaminoglycans

Diastereoselective auxiliary- and catalyst-controlled intramolecular aza-Michael reaction for the elaboration of enantioenriched 3-substituted isoindolinones. Application to the synthesis of a new pazinaclone analogue

• Romain Sallio,
• Stéphane Lebrun,
• Frédéric Capet,
• Francine Agbossou-Niedercorn,
• Christophe Michon and
• Eric Deniau

Beilstein J. Org. Chem. 2018, 14, 593–602, doi:10.3762/bjoc.14.46

• provide 3-substituted isoindolinones in good yields and diastereomeric excesses. This methodology was applied to the asymmetric synthesis of a new pazinaclone analogue which is of interest in the field of benzodiazepine-receptor agonists. Keywords: asymmetric organocatalysis; Aza-Michael reaction; phase

• stereocenter [14]. Hence, the asymmetric synthesis of functionalized 3-substituted isoindolinones using short, versatile and selective procedures is clearly a topic of current interest. Two strategies can be applied for the asymmetric synthesis of 3-substituted isoindolinones. First, diastereoselective

• (see reviews [35][36][37][38]) in intermolecular [39][40][41][42][43] and intramolecular [44][45][46] sequences. Among the latter, a short regio- and stereoselective organocatalyzed intramolecular aza-Michael reaction was reported by us for the asymmetric synthesis of several isoindolinones [20][34

Copper-catalyzed asymmetric methylation of fluoroalkylated pyruvates with dimethylzinc

• Kohsuke Aikawa,
• Kohei Yabuuchi,
• Kota Torii and
• Koichi Mikami

Beilstein J. Org. Chem. 2018, 14, 576–582, doi:10.3762/bjoc.14.44

• , many researchers including us have studied the catalytic asymmetric synthesis of optically active α-trifluoromethylated tertiary alcohols [7][8]. In these cases, one of commercially available and versatile trifluoromethyl sources, trifluoropyruvate, has been utilized for a variety of catalytic

• . Herein, we disclose the catalytic asymmetric methylation of trifluoropyruvate derivatives as electrophiles and dimethylzinc as a methylating nucleophile by a chiral copper catalyst. This method is also applicable to the asymmetric synthesis of various α-fluoroalkylated tertiary alcohols bearing CF2H

Recent developments in the asymmetric Reformatsky-type reaction

• Hélène Pellissier

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

• based on the use of chiral substrates and enantioselective catalytic procedures. Keywords: asymmetric (aza)-Reformatsky reaction; asymmetric synthesis; chirality; diastereoselectivity; enantioselectivity; total synthesis; Introduction The Reformatsky reaction involves the formation of β

Novel amide-functionalized chloramphenicol base bifunctional organocatalysts for enantioselective alcoholysis of meso-cyclic anhydrides

• Lingjun Xu,
• Shuwen Han,
• Linjie Yan,
• Haifeng Wang,
• Haihui Peng and
• Fener Chen

Beilstein J. Org. Chem. 2018, 14, 309–317, doi:10.3762/bjoc.14.19

• bond donor were developed and evaluated for enantioselective organocatalytic alcoholysis of meso-cyclic anhydrides. These structural diversified organocatalysts were found to induce high enantioselectivity in alcoholysis of anhydrides and was successfully applied to the asymmetric synthesis of (S

• monoester, without further purification by flash chromatography. Chloramphenicol-base-derived bifunctional organocatalysts. Design of new chloramphenicol base amide organocatalysts. Synthesis of bifunctional amide catalysts 7a–q. Asymmetric synthesis of (S)-GABOB (13). Conditions screening for asymmetric

Nucleophilic fluoroalkylation/cyclization route to fluorinated phthalides

• Masanori Inaba,
• Tatsuya Sakai,
• Shun Shinada,
• Tsuyuka Sugiishi,
• Yuta Nishina,
• Norio Shibata and
• Hideki Amii

Beilstein J. Org. Chem. 2018, 14, 182–186, doi:10.3762/bjoc.14.12

• , heptafluoropropyl, and pentafluorophenyl [24][25] groups were successfully installed at the C3-position of phthalides 1b–d. Thus, the selective formation of fluorinated phthalides 1 represents a synthetic usefulness for further applications. In particular, the asymmetric synthesis of C3-substituted phthalides is of

• asymmetric synthesis of 3-(trifluoromethyl)phthalide (1a) using a chiral auxiliary was published to date. In 2006, Pedrosa and co-workers discribed the diastereoselective nucleophilic trifluoromethylation of aldehyde 5, which was prepared by condensation of ortho-phthalaldehyde with (−)-8-benzylaminomenthol

• for the asymmetric synthesis of trifluoromethylphthalide 1a, it is desirable to reduce the amount of the chiral sources. Next, we undertook the development of a catalytic asymmetric synthesis of 1 in a one-pot manner. The results of our trial are summarized in Table 2. For the catalytic asymmetric

Recent progress in the racemic and enantioselective synthesis of monofluoroalkene-based dipeptide isosteres

• Myriam Drouin and
• Jean-François Paquin

Beilstein J. Org. Chem. 2017, 13, 2637–2658, doi:10.3762/bjoc.13.262

• the asymmetric synthesis of a monofluoroalkene using a chiral auxiliary (Scheme 13) [43]. The synthesis started with the alcohol protection of known compound 65 followed by chiral auxiliary removal and acylation of the resulting carboxylic acid. A HWE olefination was performed in two steps on 66 to

• protection. Xaa-ψ[CF=C]-Pro The first asymmetric synthesis of Xaa-ψ[CF=C]-Pro was reported in 2012 by Chang’s group with the synthesis of MeOCO-Val-ψ[(Z)-CF=C]-Pro 93 (Scheme 18) [52]. Their synthesis started with a stereoselective aldol reaction using (L)-threonine to furnish a chiral β-hydroxy

• reduction, transmetalation and asymmetric alkylation by Fujii and co-workers. Synthesis of (E)-monofluoroalkene-based dipeptide isostere by Fujii and co-workers. Diastereoselective synthesis of MeOCO-Val-ψ[(Z)-CF=C]-Pro isostere by Chang and co-workers. Asymmetric synthesis of Fmoc-Ala-ψ[(Z)-CF=C]-Pro by

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

• Matthias Wünsch,
• David Schröder,
• Tanja Fröhr,
• Lisa Teichmann,
• Sebastian Hedwig,
• Nils Janson,
• Clara Belu,
• Jasmin Simon,
• Shari Heidemeyer,
• Philipp Holtkamp,
• Jens Rudlof,
• Lennard Klemme,
• Alessa Hinzmann,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2017, 13, 2428–2441, doi:10.3762/bjoc.13.240

• order to provide a precursor of such peptidomimetics. As most amino acids have a chiral center at Cα, such amide bond surrogates need a chiral moiety. Here the asymmetric synthesis of a set of 24 N-sulfinyl propargylamines is presented. The condensation of various aldehydes with Ellman’s chiral

• trifluoromethyl nucleophiles, such as TMS–CF3 [84][85] has been described to be inefficient. Still, the asymmetric synthesis of CF3-substituted propargylamines has been described, using (R)-2-methoxy-1-phenylethan-1-amine as chiral auxiliary [86][87][88]. However, cleavage of the protective group requires

• 7vy were protected with a Boc group to give propargylamines 7wz and 7vz. Conclusion Ellman’s chiral sulfinamide has been successfully used for the asymmetric synthesis of enantiomerically pure propargylamines. An array of 24 diastereomerically pure N-sulfinyl propargylamines has been prepared, bearing

A mechanochemical approach to access the proline–proline diketopiperazine framework

• Nicolas Pétry,
• Hafid Benakki,
• Eric Clot,
• Pascal Retailleau,
• Farhate Guenoun,
• Fatima Asserar,
• Chakib Sekkat,
• Thomas-Xavier Métro,
• Jean Martinez and
• Frédéric Lamaty

Beilstein J. Org. Chem. 2017, 13, 2169–2178, doi:10.3762/bjoc.13.217

• chemists have used DKPs extensively as a synthetic platform, easily synthesized and stereochemically controlled, for the preparation of small bioactive molecules [4][5]. DKPs have also been considered as chiral auxiliaries in asymmetric synthesis [6]. Furthermore, the rigidity of the DKPs is a unique

Chiral phase-transfer catalysis in the asymmetric α-heterofunctionalization of prochiral nucleophiles

• Johannes Schörgenhumer,
• Maximilian Tiffner and
• Mario Waser

Beilstein J. Org. Chem. 2017, 13, 1753–1769, doi:10.3762/bjoc.13.170

• for further functionalizations by stereospecific nucleophilic SN2-type displacement reactions with different nucleophiles [66][85][86][87]. Accordingly, it comes as no surprise that their asymmetric synthesis has been intensively investigated in the past, either relying on asymmetric (transition

• -chlorination of β-ketoesters 1, by using N-chlorosuccinimide (14) as the Cl-transfer agent [76]. In continuation of our efforts to develop bifunctional ammonium salts D for asymmetric catalysis we have also recently investigated the asymmetric synthesis of α-chloroketoesters 12 [92]. We found that catalyst

• ][121][122] and chiral phase-transfer ion-pairing catalysis [110][111][112][113][114][115][116][117][118][119] turned out to be extremely powerful. Very remarkably, in 1988 Shioiri’s group already described the asymmetric synthesis of differently substituted α-hydroxy ketones 16 under chiral phase

Mechanochemical enzymatic resolution of N-benzylated-β³-amino esters

• Mario Pérez-Venegas,
• Gloria Reyes-Rangel,
• Adrián Neri,
• Jaime Escalante and
• Eusebio Juaristi

Beilstein J. Org. Chem. 2017, 13, 1728–1734, doi:10.3762/bjoc.13.167

• preparation of β-amino acids, especially protocols leading to products with high enantiomeric excess (ee), which are required to test the pharmacological activity of each enantiomer [11][12][13]. In this regard, several methods for the asymmetric synthesis of β-amino acids have been documented [14][15][16][17

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

Bifunctional organocatalysts for the asymmetric synthesis of axially chiral benzamides

• Ryota Miyaji,
• Yuuki Wada,
• Akira Matsumoto,
• Keisuke Asano and
• Seijiro Matsubara

Beilstein J. Org. Chem. 2017, 13, 1518–1523, doi:10.3762/bjoc.13.151

• significantly contributed to the field of asymmetric synthesis [1][2][3][4][5][6]. In these catalysts, (thio)urea and tertiary amino functional groups cooperatively activate a nucleophile and an electrophile simultaneously, in a suitable spatial configuration. Thus, they enable various stereoselective addition

• have recently demonstrated that bifunctional organocatalysts can also be applied to the asymmetric synthesis of axially chiral compounds (biaryls bearing isoquinoline N-oxides or quinolines and phenolic moieties) by translating a specific conformation, recognized by bifunctional organocatalysts, into

Construction of highly enantioenriched spirocyclopentaneoxindoles containing four consecutive stereocenters via thiourea-catalyzed asymmetric Michael–Henry cascade reactions

• Yonglei Du,
• Jian Li,
• Kerong Chen,
• Chenglin Wu,
• Yu Zhou and
• Hong Liu

Beilstein J. Org. Chem. 2017, 13, 1342–1349, doi:10.3762/bjoc.13.131

• , Zu Chong Zhi Road, Shanghai 201203, China University of Chinese Academy of Sciences, NO.19A Yuquan Road, Beijing 100049, China 10.3762/bjoc.13.131 Abstract The thiourea-catalyzed asymmetric synthesis of highly enantioenriched spirocyclopentaneoxindoles containing chiral amide functional groups using

• spirocyclopentaneoxindoles. Keywords: asymmetric synthesis; four consecutive stereocenters; Michael–Henry cascade reactions; spirocyclopentaneoxindoles; thioureas; Introduction The spirocyclic oxindole core represents an important scaffold that is encountered frequently in many biologically active molecules and natural

• products (Figure 1) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Despite many advances in asymmetric synthesis in the construction of heterocyclic spirooxindoles in the past decade [2][4][11][20][21][22], the development of general and practical strategies to obtain saturated

Studies directed toward the exploitation of vicinal diols in the synthesis of (+)-nebivolol intermediates

• Runjun Devi and
• Sajal Kumar Das

Beilstein J. Org. Chem. 2017, 13, 571–578, doi:10.3762/bjoc.13.56

• asymmetric synthesis of (R)-1-((R)-6-fluorochroman-2-yl)ethane-1,2-diol, (R)-1-((S)-6-fluorochroman-2-yl)ethane-1,2-diol and (S)-6-fluoro-2-((R)-oxiran-2-yl)chroman, which have been used as late-stage intermediates for the asymmetric synthesis of the antihypertensive drug (S,R,R,R)-nebivolol. Noteworthy is

Combined experimental and theoretical studies of regio- and stereoselectivity in reactions of β-isoxazolyl- and β-imidazolyl enamines with nitrile oxides

• Ilya V. Efimov,
• Marsel Z. Shafikov,
• Nikolai A. Beliaev,
• Natalia N. Volkova,
• Tetyana V. Beryozkina,
• Wim Dehaen,
• Zhijin Fan,
• Viktoria V. Grishko,
• Gert Lubec,
• Pavel A. Slepukhin and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2016, 12, 2390–2401, doi:10.3762/bjoc.12.233

• crystalline compounds, ligands for asymmetric synthesis, and they are also convenient reagents in organic synthesis [1]. Although bicyclic assemblies of azoles exhibit interesting chemical properties and biological activities [1][7][8][9][10][11] isoxazoles conjugated to other azole rings are poorly presented

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

• stereochemical aspects, this review article provides a summary on applications in natural product synthesis. Moreover, current limitations and future directions in this area of chemistry are discussed. Keywords: asymmetric synthesis; natural products; oxidation catalysis; tetrahydrofurans; total synthesis