COAP‐Pd Catalyzed Asymmetric Formal [3+2] Cycloaddition for Optically Active Multistereogenic Spiro Cyclopentane‐Indandiones Bearing Cyclic N‐Sulfonyl Ketimine Skeletons

We reported a chiral oxamide‐phosphine ligand (COAP‐Ph)‐Pd‐catalyzed asymmetric [3+2] cycloaddition reaction between vinyl cyclopropane derived from 1,3‐indanedione and 2‐vinylcyclopropane‐1,1‐dicarboxylates with cyclic sulfonyl 1‐azadienes. The corresponding reactions provided a series of enantiomerically active spiro cyclopentane‐indandione and cyclopentane structures bearing three consecutive stereogenic centers in good yields with good diastereo‐ and enantioselectivity. The COAP‐Pd complex serves not only to promote generation of chiral π‐allyl‐palladium intermediates and induce the asymmetry of the reaction, but also depress the background reaction.