Total Synthesis of an Atropisomer of the Schisandra Triterpenoid Schiglautone A. Issue 47 (25th October 2018)

• Record Type: Journal Article
• Authors: Ma, Binjie; Zhao, Yifan; He, Chi; Ding, Hanfeng
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 47(2018)
• Page Start: 15567
• Page End: 15571
• Publication Date: 2018-10-25
• Subjects: atropisomers -- radical reactions -- ring-closing metathesis -- terpenoids -- total synthesis; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201809076
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: 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. Abstract : One is not like the other : A diastereoselective approach for the total synthesis of an unusual atropisomer of the Schisandra triterpenoid schiglautone A is described. The key features are two sequential Ti III ‐catalyzed radical reactions, a ring‐closing metathesis, and a substrate‐controlled Michael addition.