A stereoselective synthesis of 1,2-diarylethenyl ethyl ethers via the carbocupration-cross coupling sequence

Article abstract of DOI:10.1016/0040-4020(96)00794-6

The synthesis of vinyl ethers [Ph(EtO)C= CHAr] was carried out by a sequence of carbocupration of ethoxyethyne with phenylcopper(I) followed by the palladium-catalyzed crosscoupling reaction of the resulting 2-ethoxyvinylcopper(I) complex with iodoarenes. The 2-ethoxyvinylcopper(I) species thus obtained were sufficiently stable to undergo the cross-coupling reaction at 0-20°C in the presence of a catalytic amount of PdCl₂(dppf) or Pd(PPh₃)₄ and 1 equivalent of ZnBr₂. The syntheses of 2-phenylbenzo[b]furan and 2-phenylindole demonstrated the utility of the present one-pot, two-step procedure for the synthesis of vinyl ethers.