Asymmetric Total Synthesis of Dankasterones A and B and Periconiastone A Through Radical Cyclization
Pengquan Chen, Cheng Wang, Yang Rui, Hongjin Xu, Jinghua Wu, Huanfeng Jiang, Kai Chen, Zhiqiang Ma
Abstract
We describe herein the assembly of the cis-decalin framework through radical cyclization initiated by metal-catalyzed hydrogen atom transfer (MHAT), further applied it in the asymmetric synthesis of dankasterones A and B and periconiastone A. Position-selective C-H oxygenation allowed for installation of the necessary functionality. A radical rearrangement was adopted to create 13(14→8)abeo-8-ergostane skeleton. Interconversion of dankasterone B and periconiastone A was realized through biomimetic intramolecular aldol and retro-aldol reactions. The MHAT-based approach, serves as a new dissection means, is complementary to the conventional ways to establish cis-decalin framework.