Pd- and Rh-Catalyzed Hydroarylation of γ-(2-Methoxycarbonylphenyl)propargylic Alcohols: Approaches to 4- or 5-Substituted Seven-Membered Benzolactones and 3,3-Disubstituted Phthalides

J Org Chem. 2015 Jul 17;80(14):6986-95. doi: 10.1021/acs.joc.5b00663. Epub 2015 Jul 6.

Abstract

A study of the palladium-catalyzed hydroarylation/hydrovinylation reaction of γ-(2-methoxycarbonylphenyl)propargylic alcohols with aryl iodides/vinyl triflates and of the rhodium-catalyzed one with organoboron derivatives is described. The opposite regiochemical outcome of the two processes allows an easy selective approach to 5- or 4-substituted benzoxepin-1(3H)-ones by combining the hydroarylative/hydrovinylative step with cyclocondensation between -OH and -COOMe groups in the intermediate γ,γ-disubstituted or β,γ-disubstituted allylic alcohols. A one-flask procedure to give benzo[c]oxepin-1(3H)-ones directly from the starting alkyne has been also developed. Treatment of crude γ,γ-disubstituted allylic alcohols with NaOH, followed by acidification, affords 3,3-disubstituted phthalides.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkynes / chemistry*
  • Benzofurans / chemistry*
  • Catalysis
  • Lactones / chemistry*
  • Molecular Structure
  • Palladium / chemistry
  • Propanols / chemistry*
  • Rhodium / chemistry

Substances

  • Alkynes
  • Benzofurans
  • Lactones
  • Propanols
  • allyl alcohol
  • Palladium
  • phthalide
  • Rhodium