Utilizing Vinylcyclopropane Reactivity: Palladium‐Catalyzed Asymmetric [5+2] Dipolar Cycloadditions

Vinylcyclopropanes (VCPs) are commonly used in transition‐metal‐catalyzed cycloadditions, and the utilization of their recently realized reactivities to construct new cyclic architectures is of great significance in modern synthetic chemistry. Herein, a palladium‐catalyzed, visible‐light‐driven, asymmetric [5+2] cycloaddition of VCPs with α‐diazoketones is accomplished by switching the reactivity of the Pd‐containing dipolar intermediate from an all‐carbon 1,3‐dipole to an oxo‐1,5‐dipole. Enantioenriched seven‐membered lactones were produced with good reaction efficiencies and selectivities (23 examples, 52–92 % yields with up to 99:1 er and 12.5:1 dr). In addition, computational investigations were performed to rationalize the observed high chemo‐ and periselectivities. By switching the reactivity of Pd‐containing dipolar intermediates from all‐carbon 1,3‐dipoles to oxo‐1,5‐dipoles, Pd‐catalyzed asymmetric [5+2] cycloadditions of vinylcyclopropanes (VCPs) with photogenerated ketenes are achieved. A variety of chiral seven‐membered lactone‐fused polycyclic molecules are produced with good reaction efficiency and selectivity.