Cobalt Catalyzed Z -Selective Hydroboration of Terminal Alkynes and Elucidation of the Origin of Selectivity

Jennifer V. Obligacion, Jamie M. Neely, Aliza N. Yazdani, Iraklis Pappas, Paul J. Chirik

Research output: Contribution to journalArticle

133 Scopus citations

Abstract

A bis(imino)pyridine cobalt-catalyzed hydroboration of terminal alkynes with HBPin (Pin = pinacolate) with high yield and (Z)-selectivity for synthetically valuable vinylboronate esters is described. Deuterium labeling studies, stoichiometric experiments, and isolation of catalytically relevant intermediates support a mechanism involving selective insertion of an alkynylboronate ester into a Co-H bond, a pathway distinct from known precious metal catalysts where metal vinylidene intermediates have been proposed to account for the observed (Z) selectivity. The identity of the imine substituents dictates the relative rates of activation of the cobalt precatalyst with HBPin or the terminal alkyne and, as a consequence, is responsible for the stereochemical outcome of the catalytic reaction.

Original languageEnglish (US)
Pages (from-to)5855-5858
Number of pages4
JournalJournal of the American Chemical Society
Volume137
Issue number18
DOIs
StatePublished - May 13 2015

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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