Intermolecular Stetter Reactions on Morita‐Baylis‐Hillman Adducts: an Approach to Highly Functionalized 1,4‐Dicarbonyl Compounds

Abstract

Abstract We reported herein an N ‐heterocyclic carbene (NHC)‐mediated intermolecular Stetter reaction between oxidized Morita‐Baylis‐Hillman (MBH) adducts and a variety of aldehydes. This protocol allows the synthesis of highly functionalized 1,4‐dicarbonyl compounds. The reaction is an alternative approach to these compounds using commercially available starting materials. This metal‐free process exhibits a wide substrate scope, excellent atom economy, compatibility with functionalized substrates and mild reaction conditions. The 1,4‐dicarbonyl compounds were prepared in two steps via MBH reactions with overall yields up to 99 %. This protocol is easily scalable. The synthetic usefulness of this method was demonstrated in a high yield synthesis of a tri‐substituted pyrrole used as an advanced intermediate in the total synthesis of kinase inhibitors as well as in the synthesis of another heterocycles.