A Concise Synthesis of (S)-(+)-Ginnol Based on Catalytic Enantioselective Addition of Commercially Unavailable Di(n-alkyl)zinc to Aldehydes and Ketones
A Concise Synthesis of (S)-(+)-Ginnol Based on Catalytic Enantioselective Addition of Commercially Unavailable Di(n-alkyl)zinc to Aldehydes and Ketones
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DOI：
10.1055/s-0030-1258129
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发表时间：
2010-08-01
期刊：
影响因子：
2
通讯作者：
Ishihara, Kazuaki
中科院分区：
文献类型：
--
作者：
Hatano, Manabu;Mizuno, Tomokazu;Ishihara, Kazuaki
开发了市售二（正烷基）锌试剂与醛和酮的催化对映选择性正烷基加成反应，该试剂是通过使用格氏试剂的 Charette 程序的改进版本制备的。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) 催化过程中的副反应，必须在无溶剂条件下制备 ZnCl2/NaOMe/RMgCl 摩尔比为 1:2.5:1.6 的二(正烷基)锌试剂。通过二十烷醛的催化对映选择性正壬酰化，首次轻松一步合成了光学纯的 (S)-(+)-ginnol (17)。
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 1:2.5:1.6 molar ratio of ZnCl2/NaOMe/RMgCl under solvent-free conditions was essential. Optically pure (S)-(+)-ginnol (17) was readily synthesized in one step for the first time by the catalytic enantioselective n-nonylation of icosanal.