Phosphine-Catalyzed Intermolecular Dienylation of Alkynoate with para-Quinone Methides

J Org Chem. 2021 Jul 2;86(13):8590-8599. doi: 10.1021/acs.joc.1c00226. Epub 2021 Jun 24.

Abstract

An interesting remote δ-C 1,6-addition and an isomerization cascade reaction for phosphine-catalyzed activated alkynes have been disclosed. The products featuring a functional diene and a 1,1-diaryl methyl motif have been obtained in moderate to good yields (30-86%) by applying para-quinone methides (p-QMs) and δ-substituted alkynoate with tributylphosphine (PnBu3) catalysis, along with high regioselectivity and stereoselectivity (dr > 20:1). The wide scope of compatible substrates (35 examples), such as indolyl, oxindolyl, ester, and cinnamyl, expand the utility of this methodology. A plausible mechanism and some applications of it have also been presented.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkynes
  • Catalysis
  • Indolequinones*
  • Phosphines

Substances

  • Alkynes
  • Indolequinones
  • Phosphines
  • quinone methide
  • phosphine