Visible Light Promoted de Mayo Type Reaction of Bicyclo[1.1.0]butanes

Abstract We reported herein a visible light mediated de Mayo‐type reaction between 1,3‐diketones and BCB. The reaction proceeds through a [2π+2σ] cycloaddition and retro‐aldol sequence, producing cis‐difunctionalized cyclobutanes in high yields with good regio‐ and diastereoselectivity.