Merging of Palladium and Organocatalysis Enabled Asymmetric Decarboxylative (2+1) Cycloadditions toward Cyclopropanes

A cascade reaction enabling enantio- and diastereoselective construction of strained cyclopropanes is described. This asymmetric (2+1) annulation process uses vinyl methylene carbonate and 2-cyanoacrylate as reaction partners in the presence of Pd(PPh₃)₄ as a precatalyst and an enantioenriched phosphoramidite ligand featuring a morpholine functionality. Mechanistic investigations unveil that the PPh₃ derived from the Pd(PPh₃)₄ and the morpholine-containing phosphoramidite work as cooperative phosphorus and Brønsted base catalysts to promote the reaction.