1155843-55-2Relevant academic research and scientific papers
Novel chiral thiourea organocatalysts for the catalytic asymmetric oxaziridination
Ji, Nan,Yuan, Jiani,Xue, Shanshan,Zhang, Junna,He, Wei
, p. 512 - 517 (2016)
Catalytic enantioselective oxaziridination is one of the challenging reactions in the oxidation of organic molecules. In this article, a series of novel chiral thiourea moleculars were synthesized from natural cinchona alkaloids and primary amines. By usi
D-Mannitol-derived novel chiral thioureas: Synthesis and application in asymmetric Henry reactions
Liu, Miaoxi,Ji, Nan,Wang, Li,Liu, Peng,He, Wei
, p. 999 - 1004 (2018/02/23)
Five novel thioureas have been obtained through multi-step reactions from D-Mannitol as starting material and applied as catalysts in the asymmetric Henry reaction. Using catalyst 7a, (1S,2R)-2-nitro-1-phenylpropan-1-ol containing two chiral centers was o
Tunable Cinchona-Based Thioureas-Catalysed Asymmetric Epoxidation to Synthetically Important Glycidic Ester Derivatives
Meninno, Sara,Zullo, Luca,Overgaard, Jacob,Lattanzi, Alessandra
supporting information, p. 913 - 918 (2017/03/27)
A novel class of synthetically important glycidic esters has been obtained via an asymmetric epoxidation of trans-α-cyano-α,β-unsaturated esters catalysed by a multifunctional Cinchona alkaloid-derived thiourea/tert-butyl hydroperoxide (TBHP) system. The glycidic esters, isolated in excellent yield with complete trans-diastereocontrol and high enantioselectivity, proved to be versatile building blocks to access challenging small targets bearing a quaternary stereocenter. (Figure presented.).
Asymmetric Epoxidation of Alkylidenemalononitriles: Key Step for One-Pot Approach to Enantioenriched 3-Substituted Piperazin-2-ones
Meninno, Sara,Vidal-Albalat, Andreu,Lattanzi, Alessandra
supporting information, p. 4348 - 4351 (2015/09/15)
The first enantioselective epoxidation of readily available alkylidenemalononitriles has been developed by using a multifunctional cinchona derived thiourea as the organocatalyst and cumyl hydroperoxide as the oxidant. A new simple one-pot asymmetric epox
Highly enantioselective Michael addition of diethyl malonate to chalcones catalyzed by cinchona alkaloids-derivatived bifunctional tertiary amine-thioureas bearing multiple hydrogen-bonding donors
Liu, Yulong,Wang, Xie,Wang, Xiaoyun,He, Wei
, p. 3163 - 3166 (2014/05/06)
Chalcones are still challenge substrates in Michael reactions, and only limited success has been achieved. This work describes a highly enantioselective Michael addition of diethyl malonate with chalcones catalyzed by cinchona alkaloids-derivatived bifunctional tertiary amine-thioureas bearing multiple hydrogen-bonding donors.
Highly enantioselective michael addition of 3-aryloxindoles to phenyl vinyl sulfone catalyzed by cinchona alkaloid-derived bifunctional amine-thiourea catalysts bearing sulfonamide as multiple hydrogen-bonding donors
Zhao, Mei-Xin,Tang, Wen-Hao,Chen, Ming-Xiao,Wei, Deng-Ke,Dai, Tong-Lei,Shi, Min
, p. 6078 - 6084 (2011/11/30)
A highly enantioselective Michael addition of 3-aryloxindole to phenyl vinyl sulfone catalyzed by a quinine-derived bifunctional amine-thiourea-bearing sulfonamide as multiple hydrogen-bonding donor catalyst has been investigated. The corresponding adduct
Highly efficient and enantioselective Michael addition of acetylacetone to nitroolefins catalyzed by chiral bifunctional organocatalyst bearing multiple hydrogen-bonding donors
Shi, Xin,He, Wei,Li, Hua,Zhang, Xu,Zhang, Shengyong
supporting information; experimental part, p. 3204 - 3207 (2011/06/28)
A new efficient catalyst system for the asymmetric addition of acetylacetone to nitroolefins using a chiral bifunctional organocatalyst bearing multiple hydrogen-bonding donors was developed. When using the organocatalyst 2c derived from natural cinchona alkaloid in optimal conditions, up to 98% chemical yield and 98% ee were observed with a variety of aromatic nitroolefins.
Asymmetric organocatalytic Michael addition of Meldrum's acid to nitroalkenes: Probing the mechanism of bifunctional thiourea organocatalysts
Kataja, Antti O.,Koskinen, Ari M. P.
scheme or table, p. 205 - 223 (2010/08/22)
The asymmetric Michael addition of Meldrum's acid to nitroalkenes was studied using a novel type of Cinchona alkaloid-based bifunctional thiourea organocatalyst. The functionality of the thiourea catalysts was also probed by preparing and testing thiourea-N-methylated analogues of the well-known bis-(3,5-trifluoromethyl)phenyl-substituted catalyst. ARKAT USA, Inc.
A simple organocatalytic enantioselective synthesis of pregabalin
Bassas, Oriol,Huuskonen, Juhani,Rissanen, Kari,Koskinen, Ari M.P.
experimental part, p. 1340 - 1351 (2009/07/26)
This paper describes a new procedure for the enantioselective synthesis of the important anticonvulsant drug Pregabalin, which shows biological properties as the (S) enantiomer only. The key step of the synthetic sequence is the Michael addition reaction of Meldrum's acid to a nitroalkene mediated by a quinidine derived thiourea. A variety of novel catalysts bearing different groups at the thiourea moiety were synthesized and tested. The most successful catalyst that incorporates a trityl substituent provided up to 75 % ee of (S)- 4. The conjugate addition reaction was carried out on a multigram scale with low loadings of catalyst (10 mol-%). Moreover, the catalyst can be recycled showing the same capability in chemical yield and asymmetric induction. Then, hydrogenation of nitroalkane 4 followed by decarboxylation of diacid 5 provides Pregabalin hydrochloride in 59% overall yield. Enantioenrichment by crystallization of the free amino acid 1 improves the (S)/(R) enantiomeric ratio to 9:1. ? Wiley-VCII Verlag GmbH & Co. KGaA.
