Faculty of Pharmaceutical Sciences , Toho University , 2-2-1 Miyama , Funabashi , Chiba 274-8510 , Japan.
The Institute of Scientific and Industrial Research (ISIR) , Osaka University , Mihogaoka, Ibaraki-shi , Osaka 567-0047 , Japan.
J Org Chem. 2019 Dec 20;84(24):16268-16277. doi: 10.1021/acs.joc.9b02886. Epub 2019 Dec 12.
The first total synthesis of (-)-graminin A is described. Key features of our synthetic approach involve a palladium-catalyzed asymmetric cyclization carbonylation of prochiral propargylic acetate, conversion of the orthoester product into methyl 4-oxo-3-furancarboxylate, and copper complex-mediated aldol condensation of (+)-gregatin B bearing a diene moiety. A new synthesis of (+)-gregatin B and the first synthesis of (-)-graminin A were achieved.
首次全合成 (-)-graminin A 的方法被描述。我们的合成方法的关键特点包括手性炔丙基乙酸酯的钯催化不对称环化羰基化、将邻酯产物转化为甲基 4-氧代-3-呋喃羧酸酯，以及带有二烯部分的 (+)-gregatin B 的铜配合物介导的羟醛缩合。实现了 (+)-gregatin B 的新合成和 (-)-graminin A 的首次合成。
