Rhodium-Catalyzed Enantioselective Cyclizations of γ-Alkynylaldehydes with Acyl Phosphonates: Ligand- and Substituent-Controlled C–P or C–H Bond Cleavage

It has been established that a cationic rhodium(I)/(R)-H(8)-BINAP or (R)-Segphos complex catalyzes two modes of enantioselective cyclizations of γ-alkynylaldehydes with acyl phosphonates via C-P or C-H bond cleavage. The ligands of the Rh(I) complexes and the substitutents of both γ-alkynylaldehydes and acyl phosphonates control these two different pathways.