Enantioselective Total Syntheses of Manginoids A and C and Guignardones A and C
Yan Zong, Zejun Xu, Rongxiu Zhu, Ai‐Hong Su, Xuyuan Liu, Ming‐Zhu Zhu, Jingjing Han, Jiao‐Zhen Zhang, Yuliang Xu, Hong‐Xiang Lou
Abstract
An enantioselective synthetic approach for preparing manginoids and guignardones, two types of biogenetically related meroterpenoids, is reported. This bioinspired and divergent synthesis employs an oxidative 1,3-dicarbonyl radical-initiated cyclization and cyclodehydration of the common precursor to forge the central ring of the manginoids and guignardones, respectively, at a late stage. Key synthetic steps include silica-gel-promoted semipinacol rearrangement to form the 6-oxabicyclo[3.2.1]octane skeleton and the Suzuki-Miyaura reaction of vinyl bromide to achieve fragment coupling. This synthesis protocol enables the asymmetric syntheses of four fungal meroterpenoids from commercially available materials.