A Highly Catalytic Asymmetric Conjugate Addition:  Synthesis of the C14−C20 Fragment of Antibiotic TMC-151A, Siphonarienal and Siphonarienone

A highly selective and general method for the synthesis of enantiopure deoxypropionates via the iterative application of CuI-Tol-BINAP-catalyzed asymmetric conjugate addition is described. This method gives access to all possible stereoisomers since both syn- and anti-deoxypropionates were obtained in high diastereoselectivities. The usefulness of the method is further exemplified by the preparation of two marine organisms, siphonarienal and siphonarienone, from commercially available trans-2-hexenoate.