Palladium-catalyzed trans-selective alkynylation–alkylation tandem process for the synthesis of (E)-3-alkyl-1-trialkylsilyl-3-alken-1-ynes
摘要:
The Pd-catalyzed trans-selective monoalkynylation of 1,1-dihalo-l-alkenes with XZnC CSiMe3, where X is Br or Cl, can proceed generally in excellent yields in the presence of Pd(DPEphos)Cl-2 or Pd(dppf)Cl-2, and subsequent alkylation with methyl- and ethylzincs can proceed in excellent yields with >= 98% retention of configuration in the presence of Pd((BU3P)-B-t)(2) as a catalyst. (c) 2005 Elsevier Ltd. All rights reserved.