Synthesis of Fused-Housane Derivatives via Intramolecular [2 + 2] Photocycloaddition

Herein, we describe a [2 + 2] photocycloaddition of cyclopropenes bearing a styryl group to prepare housane derivatives. The reaction occurs via selective excitation of the styrene fragment, enabling a completely stereoselective stepwise [2 + 2] cycloaddition. Fused-housane derivatives with an unprecedented substitution pattern are prepared in a simple manner using convenient visible light.