Palladium-Catalyzed Enantioselective Cyclization of Silyloxy-1,6-Enynes

The enantioselective intramolecular addition of silyl enol ethers and silyl ketene aminals onto alkyne is described. The reaction employs DTBMSegphos−Pd(II) or Binaphane−Pd(II) complexes as catalysts for the formation of methylene cyclopentane adducts from 1,6-enyne precursors. The utility of this reaction is illustrated by its application to the total synthesis of the cytotoxic cyclolaurane-type sesquiterpene, (−)-laurebiphenyl.