Enantioselective N-Heterocyclic Carbene Catalysis via the Dienyl Acyl Azolium

Rachel M Gillard; Jared E M Fernando; David W Lupton

doi:10.1002/anie.201712604

Enantioselective N-Heterocyclic Carbene Catalysis via the Dienyl Acyl Azolium

Angew Chem Int Ed Engl. 2018 Apr 16;57(17):4712-4716. doi: 10.1002/anie.201712604. Epub 2018 Mar 24.

Authors

Rachel M Gillard¹, Jared E M Fernando¹, David W Lupton¹

Affiliation

¹ School of Chemistry, Monash University, Clayton, 3800, Victoria, Australia.

PMID: 29380549
DOI: 10.1002/anie.201712604

Abstract

Herein we report the enantioselective N-heterocyclic carbene catalyzed (4+2) annulation of the dienyl acyl azolium with enolates. The reaction exploits readily accessible acyl fluorides and TMS enol ethers to give a range of highly enantio- and diastereo-enriched cyclohexenes (most >97:3 er and >20:1 dr). The reaction was found to require high nucleophilicity NHC catalysts with mechanistic studies supporting a stepwise 1,6-addition/β-lactonization.

Keywords: 1,6-addition; N-heterocyclic carbene; dienyl acyl azolium; enantioselective catalysis; β-lactonization.

Publication types

Research Support, Non-U.S. Gov't