A Concise Synthesis of (S)-(+)-Ginnol Based on Catalytic Enantioselective Addition of Commercially Unavailable Di(n-alkyl)zinc to Aldehydes and Ketones
作者:Kazuaki Ishihara、Manabu Hatano、Tomokazu Mizuno
DOI:10.1055/s-0030-1258129
日期:2010.8
Catalytic, enantioselective n-alkyl addition of commercially unavailable di(n-alkyl)zinc reagents, which were prepared by a refined version of Charette's procedure with Grignard reagents, to aldehydes and ketones was developed. To minimize the side reactions in the catalysis by chiral phosphoramide ligand (1) or 3,3'-diphosphoryl-BINOL ligand (2), a preparation of di(n-alkyl)zinc reagents with a 1:2
开发了商业上无法获得的二(正烷基)锌试剂的催化、对映选择性正烷基加成反应,这些试剂是通过使用格氏试剂的 Charette 程序的精制版本制备的,与醛和酮进行加成。为了最大限度地减少手性磷酰胺配体 (1) 或 3,3'-二磷酰基-BINOL 配体 (2) 催化中的副反应,制备摩尔比为 1:2.5:1.6 的二(正烷基)锌试剂无溶剂条件下的 ZnCl 2 /NaOMe/RMgCl 是必不可少的。光学纯的 (S)-(+)-ginnol (17) 第一次通过二十烷醛的催化对映选择性正壬基化很容易在一个步骤中合成。