Enantioselective N‐Heterocyclic Carbene Catalysis via the Dienyl Acyl Azolium
作者:Rachel M. Gillard、Jared E. M. Fernando、David W. Lupton
DOI:10.1002/anie.201712604
日期:2018.4.16
Herein we report the enantioselective N‐heterocycliccarbenecatalyzed (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
The reaction of silyl enol ethers with phthaloyl dichloride afforded alkylidene-3-oxo-3H-isobenzofurans with very good E/Z-selectivity. cyclizations - O-heterocycles - phthalic acid derivatives - silyl enol ethers