First Generation Cysteine- and Methionine-Derived Oxazolidine and Thiazolidine Ligands for Palladium-Catalyzed Asymmetric Allylations
作者:Paulo H. Schneider、Henri S. Schrekker、Claudio C. Silveira、Ludger A. Wessjohann、Antonio L. Braga
DOI:10.1002/ejoc.200300675
日期:2004.6
series of enantiopure oxazolidine-thioether and thiazolidine-alcohol ligands have been synthesized from L-cysteine, S-methyl-L-cysteine, and L-methionine in a straightforward manner that allows numerous structural variations to be formed. These types of ligands have not previously been used in asymmetric palladium-catalyzed allylations and their efficacy was explored in the reaction of rac-1,3-diphenyl-2-propenyl
已从 L-半胱氨酸、S-甲基-L-半胱氨酸和 L-甲硫氨酸以允许形成多种结构变化的直接方式合成了一系列新的对映体纯恶唑烷-硫醚和噻唑烷-醇配体。这些类型的配体以前没有用于不对称钯催化的烯丙基化,并且在 rac-1,3-二苯基-2-丙烯基乙酸酯与丙二酸二甲酯的反应中探索了它们的功效。该反应以极好的收率和良好的对映选择性进行。衍生自 N-苄基-2,2-二甲基-4-(2-噻丙基)恶唑烷 (12) 的钯催化剂以定量收率和 94% 的对映体过量提供烯丙基化产物。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)