Preparative and mechanistic studies toward the rational development of catalytic, enantioselective selenoetherification reactions

Scott E. Denmark, Dipannita Kalyani, William R. Collins

Research output: Contribution to journalArticle

Abstract

A systematic investigation into the Lewis base catalyzed, asymmetric, intramolecular selenoetherification of olefins is described. A critical challenge for the development of this process was the identification and suppression of racemization pathways available to arylseleniranium ion intermediates. This report details a thorough study of the influences of the steric and electronic modulation of the arylselenenyl group on the configurational stability of enantioenriched seleniranium ions. These studies show that the 2-nitrophenyl group attached to the selenium atom significantly attenuates the racemization of seleniranium ions. A variety of achiral Lewis bases catalyze the intramolecular selenoetherification of alkenes using N-(2-nitrophenylselenenyl)succinimide as the electrophile along with a Brønsted acid. Preliminary mechanistic studies suggest the intermediacy of ionic Lewis base-selenium(II) adducts. Most importantly, a broad survey of chiral Lewis bases revealed that 1,1′-binaphthalene-2,2′-diamine (BINAM)-derived thiophosphoramides catalyze the cyclization of unsaturated alcohols in the presence of N-(2-nitrophenylselenenyl)succinimide and methanesulfonic acid. A variety of cyclic seleno ethers were produced in good chemical yields and in moderate to good enantioselectivities, which constitutes the first catalytic, enantioselective selenofunctionalization of unactivated olefins.

Original languageEnglish (US)
Pages (from-to)15752-15765
Number of pages14
JournalJournal of the American Chemical Society
Volume132
Issue number44
DOIs
StatePublished - Nov 10 2010

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ASJC Scopus subject areas

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

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