Palladium-catalyzed trans-selective alkynylation–alkylation tandem process for the synthesis of (E)-3-alkyl-1-trialkylsilyl-3-alken-1-ynes

The Pd-catalyzed trans-selective monoalkynylation of 1,1-dihalo-1-alkenes with XZnCtriple bond; length of mdashCSiMe3, where X is Br or Cl, can proceed generally in excellent yields in the presence of Pd(DPEphos)Cl2 or Pd(dppf)Cl2, and subsequent alkylation with methyl- and ethylzincs can proceed in excellent yields with ≥98% retention of configuration in the presence of Pd(tBu3P)2 as a catalyst.