Amine-Release Annulation of Enaminones: Bimetallic Co-Catalytic Synthesis of Cyclopentadienes from Alkynes

An efficient Au(III)/Ag(I) co-catalytic platform has been established for the synthesis of cyclopentadienes through amine-release annulation of enaminones with alkynes. Vinylcarbenoids that were generated from 1,2-migration of propargyl esters may undergo a tandem annulation process with enaminones to give aminocyclopentenes as key intermediates. The bimetal catalytic system is compatible with a broad substrate scope under mild reaction conditions. The obtained cyclopentadienes are allowed to undergo late-stage modifications into complex molecules with high chemo- and regioselectivities.