A Novel Bis-Thiourea Organocatalyst for the Asymmetric Aza-Henry Reaction
作者:Constantinos Rampalakos、William D. Wulff
DOI:10.1002/adsc.200800214
日期:2008.8.4
A novelbis-thiourea BINAM-based catalyst for the asymmetricaza-Henryreaction has been developed. This catalyst promotes the reaction of N-Boc imines with nitroalkanes to afford beta-nitroamines with good yields and high enantioselectivities. This catalyst has the advantage that it can be prepared in a single step from commercially available materials. A model is proposed for the catalyst action
The first example of the preparation of enantiomerically pure atropisomeric mustard oils is described. Both enantiomers were obtained by simple acylation of the corresponding diamines with thiophosgene. (C) 1997 Elsevier Science Ltd.
Polythioureas: Main Chain Chiral Polymers in Hydride Transfer Hydrogenation
Chiral polythioureas have been synthesized and tested in asymmetric hydride transfer reduction of ketones with ruthenium. With polyurea 18, 70% ee was attained for acetophenone reduction; after filtration, it can be reused at least four times without any detectable loss of activity and only a slight decrease in selectivity. Various aryl alkylketones were reduced with the same system and up to 84%
手性聚硫脲已被合成并在酮与钌的不对称氢化物转移还原中进行了测试。使用聚脲 18,苯乙酮还原达到 70% ee;过滤后,它可以重复使用至少四次,而没有任何可检测到的活性损失,选择性仅略有下降。使用相同的系统还原各种芳基烷基酮,使用异丙基苯基酮测得的 ee 高达 84%。
Exploring the Conversion of Macrocyclic 2,2′-Biaryl Bis(thioureas) into Cyclic Monothioureas: An Experimental and Computational Investigation
Macrocyclic bis(thioureas) derived from 2,2′-biphenyl and binaphthyl skeletons have been synthesized by reaction of 2,2′-diaminobiaryl and 2,2′-bis(isothiocyanato)biaryl derivatives. The splitting of these bis(thioureas) into two units of the respective cyclic monothioureas has been monitored by NMR, shedding some light on the factors that control these processes. Additionally, a computational study