Phosphazene-catalyzed desymmetrization of cyclohexadienones by dithiane addition

• Matthew A. Horwitz,
• Elisabetta Massolo and
• Jeffrey S. Johnson

Beilstein J. Org. Chem. 2017, 13, 762–767, doi:10.3762/bjoc.13.75

• ; desymmetrization; dithiane; iminophosphoranes; organocatalysis; phosphazenes; Findings Desymmetrization has become a well-developed strategy for the construction of complex molecular frameworks [1][2][3][4][5][6]. Cyclohexadienones are multipurpose synthetic building blocks that have found a central role in

Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanyl)phenyl-1H-1,2,3-triazol-4-yl)ketones

• Gabriel P. Costa,
• Natália Seus,
• Juliano A. Roehrs,
• Raquel G. Jacob,
• Ricardo F. Schumacher,
• Thiago Barcellos,
• Rafael Luque and
• Diego Alves

Beilstein J. Org. Chem. 2017, 13, 694–702, doi:10.3762/bjoc.13.68

• ; organocatalysis; organoselenium compounds; sonochemistry; 1,2,3-triazoles; Introduction Substituted 1,2,3-triazoles are an interesting class of heterocyclic compounds distinguished by their biological activities [1][2][3] as well as in various fields of chemistry [4][5][6][7][8][9][10][11][12][13][14][15]. The

Synthesis of new pyrrolidine-based organocatalysts and study of their use in the asymmetric Michael addition of aldehydes to nitroolefins

• Alejandro Castán,
• Ramón Badorrey,
• José A. Gálvez and
• María D. Díaz-de-Villegas

Beilstein J. Org. Chem. 2017, 13, 612–619, doi:10.3762/bjoc.13.59

• aldehydes to nitroolefins and enantioselectivities up to 85% ee were achieved. Keywords: enantioselective synthesis; Michael addition; organocatalysis; pyrrolidines; synthetic methods; Introduction In the first decades of the 21st century, the enantioselective organocatalysis has witnessed a tremendous

• development [1][2][3][4] and it is now considered to be the third pillar of enantioselective catalyses together with metal complex-mediated catalysis and biocatalysis. Among the different structures usually found in organocatalysis, the five-membered secondary amine structure of pyrrolidine has proven to be a

• tuneable catalytic motifs to be used in organocatalysis starting from the chiral pool. Highly modular chiral aminodiol derivatives were obtained by the addition of organometallic reagents to chiral imines derived from (R)-glyceraldehyde – which is easily accessible from D-mannitol – and these were

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

• Flavio Fanelli,
• Giovanna Parisi,
• Leonardo Degennaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

• . The optimized conditions were suitable for the functionalization of 2-fluoropyridine, 2,6- difluoropyridine and 4-(trifluoromethyl)pyridine leading to products 7a–g reported in Scheme 10. Another promising field is the sustainable flow organocatalysis, and recently Pericàs reported an interesting

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

• Pavel Nagorny and
• Zhankui Sun

Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283

• of organocatalysis. While traditional hydrogen bond donors containing N–H and O–H moieties have been effectively used for electrophile activation, activation based on other types of non-covalent interactions is less common. This mini review highlights recent progress in developing and exploring new

• organic catalysts for electrophile activation through the formation of C–H hydrogen bonds and C–X halogen bonds. Keywords: C–H hydrogen bond; counteranion activation; electrophile activation; halogen bond donor; hydrogen bond donor; organocatalysis; Review Introduction Over the past century chemists

• design of small molecule-based catalysts mimicking enzymatic function. A significant number of such efforts has been dedicated to designing new catalysts to enhance the electrophilicity of organic molecules through non-covalent interactions, and many important areas of organocatalysis have emerged from

Copper-catalyzed asymmetric sp³ C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

• Pierre Querard,
• Inna Perepichka,
• Eli Zysman-Colman and
• Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

• of THIQs with arylboronic esters via asymmetric organocatalysis methodology [25][28]. The use of chiral tartaric acid derivatives, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and high temperature (70 °C) were found to be the optimal conditions to obtain the desired arylated product with

Towards the development of continuous, organocatalytic, and stereoselective reactions in deep eutectic solvents

• Davide Brenna,
• Elisabetta Massolo,
• Alessandra Puglisi,
• Sergio Rossi,
• Giuseppe Celentano,
• Maurizio Benaglia and
• Vito Capriati

Beilstein J. Org. Chem. 2016, 12, 2620–2626, doi:10.3762/bjoc.12.258

• . Keywords: continuous process; DES; organocatalysis; proline; stereoselective aldol reaction; Introduction The aldol reaction is a powerful synthetic tool to create new C–C bonds [1]. It offers several possibilities to control the stereochemical outcome of the process and to afford stereochemically defined

• when using an apparently simple organocatalyst such as L-proline. These observations have important implications in the future design of chiral catalysts, thereby opening the floodgates to new intriguing opportunities for organocatalysis in unconventional reaction media. Experimental set-up I: test

Highly chemo-, enantio-, and diastereoselective [4 + 2] cycloaddition of 5H-thiazol-4-ones with N-itaconimides

• Shuai Qiu,
• Choon-Hong Tan and
• Zhiyong Jiang

Beilstein J. Org. Chem. 2016, 12, 2293–2297, doi:10.3762/bjoc.12.222

• ) were obtained for a series of spirocyclic 1,4-sulfur-bridged piperidinone-based succinimides. Keywords: [4 + 2] annulation; asymmetric organocatalysis; dipeptide-based Brønsted bases; 5H-thiazol-4-ones; N-itaconimides; Introduction Sulfur-containing tetrasubstituted carbon stereocenters are widely

Correction: Recent advances in N-heterocyclic carbene (NHC)-catalysed benzoin reactions

• Rajeev S. Menon,
• Akkattu T. Biju and
• Vijay Nair

Beilstein J. Org. Chem. 2016, 12, 2124–2124, doi:10.3762/bjoc.12.201

• Interdisciplinary Science and Technology,Trivandrum 695 019, India.; Fax: +91 471 2491712; Tel: +91 471 2490406 10.3762/bjoc.12.201 Keywords: acyloin reaction; benzoin reaction; N-heterocyclic carbenes; organocatalysis; umpolung; On page 446, column 2, the sentence “Inoue and co-workers found that it promotes

Chiral ammonium betaine-catalyzed asymmetric Mannich-type reaction of oxindoles

• Masahiro Torii,
• Kohsuke Kato,
• Daisuke Uraguchi and
• Takashi Ooi

Beilstein J. Org. Chem. 2016, 12, 2099–2103, doi:10.3762/bjoc.12.199

• quaternary and tertiary stereogenic carbon centers on biologically intriguing molecular frameworks with high fidelity. Keywords: ammonium betaine; asymmetric catalysis; Mannich reaction; organocatalysis; oxindole; Introduction Chiral indole alkaloids possessing C-3 quaternary indoline frameworks are an

Economical and scalable synthesis of 6-amino-2-cyanobenzothiazole

• Jacob R. Hauser,
• Hester A. Beard,
• Mary E. Bayana,
• Katherine E. Jolley,
• Stuart L. Warriner and
• Robin S. Bon

Beilstein J. Org. Chem. 2016, 12, 2019–2025, doi:10.3762/bjoc.12.189

• -cyanobenzothiazoles; DABCO; luciferins; organocatalysis; Introduction Functionalised 2-cyanobenzothiazoles (CBTs, 1) are key building blocks for the synthesis of luciferins 3 [1][2][3], substrates of natural and engineered firefly luciferases that are widely used for bioluminescence imaging (BLI) [4][5]. The typical

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

• Maurizio Selva,
• Alvise Perosa,
• Sandro Guidi and
• Lisa Cattelan

Beilstein J. Org. Chem. 2016, 12, 1911–1924, doi:10.3762/bjoc.12.181

• therapeutics, imaging agents and packaging films and coatings [77]. Conclusion The literature survey illustrated in this review highlights three main facts. Firstly, organocatalysis by ionic liquids can be an efficient tool for base and even acid-catalyzed transesterification reactions in place of traditional

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Enantioselective addition of diphenyl phosphonate to ketimines derived from isatins catalyzed by binaphthyl-modified organocatalysts

• Hee Seung Jang,
• Yubin Kim and
• Dae Young Kim

Beilstein J. Org. Chem. 2016, 12, 1551–1556, doi:10.3762/bjoc.12.149

• organocatalyst; ketimines; organocatalysis; squaramide; Introduction α-Aminophosphonate derivatives are important compounds as structural mimics of natural α-amino acids [1][2][3]. Chiral α-aminophosphonates have been shown a wide range of biological activities including antibacterial [4] and anticancer

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

• , enantioenriched 3-hydroxyoxindole scaffolds also exist in natural products and have proven to possess promising biological activities. A large number of catalytic asymmetric strategies toward the construction of 3-hydroxyoxindoles based on transition metal catalysis and organocatalysis have been reported in the

• -substituted 3-hydroxyoxindoles and 3-hydroxyoxindole-based further transformations. Keywords: 3-hydroxyoxindoles; oxindoles; organocatalysis; spirooxindoles; transition metal catalysis; Introduction Chiral oxindoles are an important class of compounds, which widely exist in nature and have exhibited diverse

• excellent ee values (up to 97% ee) from DMTr (Di(p-methoxyphenyl)phenylmethyl)-N-protected isatins in one-pot under modified conditions. Organocatalyzed synthesis of 3-substituted 3-hydroxyoxindoles Organocatalysis has witnessed significant progress in the last decades, a large number of new organocatalysts

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• efficient platforms for bidentate coordination in metal catalysis and good precursors of carboxylic acids, ketones and aldehydes upon oxidative cleavage of the keto/diol moiety [72]. More recently, a comprehensive study on the first evidence of the utility of these acceptors in organocatalysis has been

Asymmetric α-amination of 3-substituted oxindoles using chiral bifunctional phosphine catalysts

• Qiao-Wen Jin,
• Zhuo Chai,
• You-Ming Huang,
• Gang Zou and
• Gang Zhao

Beilstein J. Org. Chem. 2016, 12, 725–731, doi:10.3762/bjoc.12.72

• organocatalysis and metal catalysis for the construction of this type of structures. For example, Chen et al. reported the first organocatalytic enantioselective amination reaction of 2-oxindoles catalyzed by biscinchona alkaloid catalysts [8]. Zhou [9][10] and Barbas [11][12], have independently reported similar

Stereoselective amine-thiourea-catalysed sulfa-Michael/nitroaldol cascade approach to 3,4,5-substituted tetrahydrothiophenes bearing a quaternary stereocenter

• Sara Meninno,
• Chiara Volpe,
• Giorgio Della Sala,
• Amedeo Capobianco and
• Alessandra Lattanzi

Beilstein J. Org. Chem. 2016, 12, 643–647, doi:10.3762/bjoc.12.63

• affording the heterocyclic products in good yields and moderate stereoselectivities. Keywords: cascade reaction; tetrahydrothiophenes; aymmetric synthesis; amine thioureas; organocatalysis; Introduction The interest toward the development of stereoselective methodologies to prepare tetrahydrothiophenes

Supported bifunctional thioureas as recoverable and reusable catalysts for enantioselective nitro-Michael reactions

• José M. Andrés,
• Miriam Ceballos,
• Alicia Maestro,
• Isabel Sanz and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2016, 12, 628–635, doi:10.3762/bjoc.12.61

• the thiourea derived from (L)-valine and 1,6-hexanediamine. The catalysts can be used in only 2 mol % loading, and reused for at least four cycles in neat conditions. The ball milling promoted additions also worked very well. Keywords: bifunctional organocatalysts; organocatalysis; stereoselective

The aminoindanol core as a key scaffold in bifunctional organocatalysts

• Isaac G. Sonsona,
• Eugenia Marqués-López and
• Raquel P. Herrera

Beilstein J. Org. Chem. 2016, 12, 505–523, doi:10.3762/bjoc.12.50

• ; bifunctional; organocatalysis; hydrogen bonding; Introduction The structural and chemical properties of the 1,2-aminoindanol scaffold 1 have transformed aminoindanol derivatives into versatile building blocks for the construction of catalysts and the efficient induction of chirality in asymmetric processes

• trifluoroethylamine moiety [3][4][5]. However, it is in the field of asymmetric organocatalysis [6][7][8] where the aminoindanol core has gained more importance, being a recurrent structural motif in several organocatalytic species. Some examples are (a) the enantioselective reduction of ketones through the in situ

• the high catalytic potential that this versatile motif exhibits [14]. The concept of bifunctionality has been extensively explored in organocatalysis in the last decade [15][16]. The bifunctional organocatalyst contains two chemical groups that interact simultaneously with the substrates. This mode of

(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• Giorgos Koutoulogenis Nikolaos Kaplaneris Christoforos G. Kokotos Department of Chemistry, National and Kapodestrian University of Athens, Panepistimiopolis 15771, Athens, Greece 10.3762/bjoc.12.48 Abstract Organocatalysis, now running its second decade of life, is being considered one of the

• chiral centers; organocatalysis; six-membered ring; thiourea; urea; Introduction During the last 15 years, organocatalysis has flourished and has been established as one of the three major pillars of asymmetric synthesis [1][2][3]. Among the modes of activation of organic molecules that have been

• )ureas have been synthesized in order to utilize both hydrogen bonding interactions and enamine formation. In the last 10 years the field has witnessed the development of some new activation modes, such as SOMO catalysis [8] and photoredox organocatalysis [9]. Six-membered rings are found in many natural

Recent advances in N-heterocyclic carbene (NHC)-catalysed benzoin reactions

• Rajeev S. Menon,
• Akkattu T. Biju and
• Vijay Nair

Beilstein J. Org. Chem. 2016, 12, 444–461, doi:10.3762/bjoc.12.47

• ; benzoin reaction; N-heterocyclic carbenes; organocatalysis; umpolung; Introduction The benzoin reaction (or condensation) is named after the product it furnishes via a catalytic assembly of two molecules of aromatic aldehydes. One molecule of the aldehyde functions as an acyl anion and the other as a

• that the cyanide anion can catalyze the union of two molecules of aromatic aldehydes to afford α-hydroxy ketones [1]. More than a century later, a thiazolium salt-catalysed benzoin reaction was reported by Ukai [2]. This may be regarded as an early example of organocatalysis using an azolium salt

• reaction remained elusive due to a variety of reasons, the toxicity of cyanide catalysts being one of them. Breslow’s discovery in 1958 of the thiazolylidene-catalysed benzoin condensation via polarity reversal of aldehydes formed the conceptual basis for the later development of NHC-organocatalysis. The

Cupreines and cupreidines: an established class of bifunctional cinchona organocatalysts

• Laura A. Bryant,
• Rossana Fanelli and
• Alexander J. A. Cobb

Beilstein J. Org. Chem. 2016, 12, 429–443, doi:10.3762/bjoc.12.46

• asymmetric organocatalysis. This fascinating class of bifunctional catalyst offers a genuine alternative to the more commonly used thiourea systems and because of the different spacing between the functional groups, can control enantioselectivity where other organocatalysts have failed. In the main, this

• . Keywords: bifunctional; cupreidine; cinchona; cupreine; organocatalysis; Introduction The cinchona alkaloids, comprising quinine (QN), quinidine (QD), cinchonidine (CD), cinchonine (CN, Figure 1), and their derivatives have revolutionized asymmetric catalysis owing to their privileged structures. The

• their derivatives in asymmetric organocatalysis over the last five years or so [13][14]. The review is organized by reaction type, beginning with the Morita–Baylis–Hillman process – one of the first reactions to utilize 6’-OH-cinchona alkaloid derivatives in asymmetric organocatalysis. The focus will

Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors

• Ming-Liang Zhang,
• Deng-Feng Yue,
• Zhen-Hua Wang,
• Yuan Luo,
• Xiao-Ying Xu,
• Xiao-Mei Zhang and
• Wei-Cheng Yuan

Beilstein J. Org. Chem. 2016, 12, 295–300, doi:10.3762/bjoc.12.31

• -pyrrol-2(3H)-ones bearing quaternary stereocenters were obtained in acceptable yield (up to 75%) and enantioselectivity (up to 73% ee). Keywords: asymmetric catalysis; bifunctional catalysts; Henry reaction; organocatalysis; 1H-pyrrole-2,3-diones; Introduction Asymmetric organocatalysis has been

Base metal-catalyzed benzylic oxidation of (aryl)(heteroaryl)methanes with molecular oxygen

• Hans Sterckx,
• Johan De Houwer,
• Carl Mensch,
• Wouter Herrebout,
• Kourosch Abbaspour Tehrani and
• Bert U. W. Maes

Beilstein J. Org. Chem. 2016, 12, 144–153, doi:10.3762/bjoc.12.16

• organocatalysis in combination with molecular oxygen has received a great deal of attention from the scientific community [4][5][6][7]. Molecular oxygen is considered to be the greenest oxidant available and it is already widely employed by the commodity chemical industry [8]. However, when looking at the