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Total Synthesis of an Atropisomer of the Schisandra Triterpenoid Schiglautone A
Author(s) -
Ma Binjie,
Zhao Yifan,
He Chi,
Ding Hanfeng
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201809076
Subject(s) - atropisomer , chemistry , stereochemistry , ring (chemistry) , metathesis , ring closing metathesis , enantioselective synthesis , schisandra , epoxide , salt metathesis reaction , combinatorial chemistry , catalysis , organic chemistry , medicine , alternative medicine , traditional chinese medicine , pathology , polymerization , polymer
A diastereoselective approach for the total synthesis of an unusual atropisomer of the Schisandra triterpenoid (±)‐schiglautone A is described. The efficient synthetic strategy features three key transformations: 1) two sequential titanium(III)‐catalyzed radical cyclization/homologation reactions to construct the trans ‐fused [6,7] bicycle as well as install the quaternary carbons at C10 and C14 with the desired stereochemistry; 2) a Claisen rearrangement followed by a ring‐closing metathesis to forge the strained nine‐membered ring; and 3) a substrate‐controlled Michael addition to enable the introduction of the C17 side‐chain with good diastereoselectivity.