Synthesis of 12,12'-azo-13,13'-diepi-Ritterazine N

J Org Chem. 2017 Jan 6;82(1):269-275. doi: 10.1021/acs.joc.6b02391. Epub 2016 Dec 16.

Abstract

A synthesis of the 12,12'-azo-analogue of ritterazine N from hecogenin is reported. Ring contraction of two 6/5 bicyclic ring systems, one trans-fused and another spiro, to 5/5 spiro ring systems is accomplished with excellent stereochemical control. Key transformations include an abnormal Baeyer-Villiger oxidation, a Norrish type I cleavage, an intramolecular dipolar [3 + 2] cycloaddition, and an intramolecular oxymecuration. Failing to uncover the β-OH ketone from the isoxazoline ring, we end up with a synthesis of a cyclic analogue of ritterazine N.

Publication types

  • Research Support, Non-U.S. Gov't