Construction of All-Carbon Quaternary Stereocenter via Indium-Catalyzed Addition of 1,3-Dicarbonyl Compounds to Simple Alkynes

摘要

Enolate anions derived from prochiral 1,3-dicarbonyl compounds are frequently used as versatile intermediates to form, upon various reactions with an electrophile, a new carbon-carbon bond with a stereochemically-defined quaternary carbon center at the alpha-position. While the alkynes activated by electron withdrawing groups are known as good Michael acceptors for the reaction with 1,3-dicarbonyl compounds, simple alkynes have not been employed as far because the electronically-unactivated C-C multiple bond is thought to be inert towards the addition of enolate anions. We recently found that indium and some other metals can promote alpha-vinylation reaction of 1,3-dicarbonyl compounds via regioselective addition of metal enolates to simple 1 -alkynes. Herein we report that a suitably designed 1,3-dicarbonyl surrogate undergoes highly diastereoselective alpha-alkenylation reaction by using simple alkynes as the electrophile in the presence of indium catalyst.