Catalytic enantioselective protoboration of disubstituted allenes. Access to alkenylboron compounds in high enantiomeric purity

Org Lett. 2014 Sep 5;16(17):4658-61. doi: 10.1021/ol5022417. Epub 2014 Aug 25.

Abstract

Proto-boryl additions to 1,1-disubstituted allenes in the presence of 1.0-5.0 mol % of chiral NHC-Cu complexes, B2(pin)2, and t-BuOH proceed to afford alkenyl-B(pin) products in up to 98% yield, >98:2 site selectivity, and 98:2 er. The enantiomerically enriched alkenylboron products can be converted to otherwise difficult-to-access alkenyl bromides, methyl ketones or carboxylic acids. What's more, the corresponding boronic acids may be used in highly stereoselective NHC-Cu-catalyzed allylic substitution reactions.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Alkadienes / chemistry*
  • Boron Compounds / chemical synthesis*
  • Boron Compounds / chemistry
  • Catalysis
  • Copper / chemistry
  • Molecular Structure
  • Stereoisomerism

Substances

  • Alkadienes
  • Boron Compounds
  • propadiene
  • Copper