Formal [4 + 2] Cycloadditions of Anhydrides and α,β-Unsaturated N-Tosyl Ketimines

Org Lett. 2019 Feb 15;21(4):1046-1049. doi: 10.1021/acs.orglett.8b04091. Epub 2019 Feb 5.

Abstract

A method for the diastereoselective synthesis of highly substituted β-enamino ketones from anhydrides and ketone-derived imines is reported. Cyclic, enolizable anhydrides undergo a base-promoted conjugate addition reaction with α,β-unsaturated N-tosyl ketimines, followed by an intramolecular acylation to give formal [4 + 2] cycloaddition products. The carboxylic acid-containing products are formed with modest selectivity for the cis-diastereomer and can be fully epimerized to the trans-diastereomer upon esterification.

Publication types

  • Research Support, Non-U.S. Gov't