Organocatalytic Enantioselective Alkylation of Aldehydes with [Fe(bpy)₃]Br₂ Catalyst and Visible Light

Abstract

Catalytic amounts (2.5 mol %) of [Fe(bpy)3]Br2 complex in the presence of visible light and the MacMillan catalyst 3 (20 mol %) are highly effective in promoting an enantioselective organocatalytic photoredox alkylation of aldehydes with various α-bromo carbonyl compounds. Reaction yields of isolated compounds and enantioselectivities are very good and comparable to the ones obtained by [Ru(bpy)3]2+, organic dyes, or semiconductors, in the presence of the same organocatalysts. The use of first-row, abundant, and cheap metals in photocatalyzed reactions can open new perspectives in stereoselective organic synthesis.