Radical Conjugate Addition of Acylsilane Enabled by Synergistic Photoredox and Lewis Acid Catalysis

Abstract

A visible-light-induced acyl radical conjugate addition to electron-deficient alkenes with acylsilane was realized by merging photoredox and Lewis acid catalysis under mild reaction conditions. Various tri- and tetra-substituted furans were obtained with good yield (up to 97%) from α,β-unsaturated ketones. Based on the experimental results and spectral analysis, a possible catalytic cycle involving 1,4-conjugate addition/ring-closure/arylation sequence was proposed. Beyond that, 1,6-acyl radical conjugate addition to para-quinone methides was also accomplished to deliver a series of α-aryl ketones by using this synergistic catalysis protocol.