Platinum-Catalyzed α,β-Unsaturated Carbene Formation in the Formal Syntheses of Frondosin B and Liphagal
作者:Khoi Q. Huynh、Curtis A. Seizert、Tarik J. Ozumerzifon、Paul A. Allegretti、Eric M. Ferreira
DOI:10.1021/acs.orglett.6b03682
日期:2017.1.6
Formal syntheses of tetracyclic terpenoids frondosin B and liphagal are described. Both synthetic routes rely on the use of platinum-catalyzed α,β-unsaturated carbene formation for the key C–C bond forming transformations. The successful route toward frondosin B utilizes a formal (4 + 3) cycloaddition, while the liphagal synthesis features the vinylogous addition of an enol nucleophile as a key step
描述了四环萜类化合物frondosin B和脂蛋白的形式合成。两种合成途径都依赖于铂催化的α,β-不饱和卡宾的形成来进行关键的CC键形成转化。往frondosin B的成功途径是利用正式的(4 + 3)环加成,而脂族合成的特征是烯醇式亲核试剂的乙烯基添加是关键步骤。讨论了这两种合成路线,揭示了对催化α,β-不饱和卡宾反应歧管中的结构要求的见解。