Double-asymmetric hydrogenation strategy for the reduction of 1,1-diaryl olefins applied to an improved synthesis of CuIPhEt, a C2-symmetric N-heterocyclic carbenoid

J Org Chem. 2013 Mar 15;78(6):2731-5. doi: 10.1021/jo3026548. Epub 2013 Feb 19.

Abstract

A library of iridium and rhodium phosphine catalysts have been screened for the double-asymmetric hydrogenation of 2,6-di-(1-phenylethenyl)-4-methylaniline to produce the C2-symmetric aniline precursor of the N-heterocyclic carbenoid CuIPhEt. The best catalyst produced the desired enantiomer in 98.6% selectivity. This rare example of a highly selective hydrogenation of a 1,1-diaryl olefin enables a four-step asymmetric synthesis of the C2-symmetric phenylethyl imidazolium ion (IPhEt) from p-toluidine and phenylacetylene and its conversion to the hydrosilylation catalyst CuIPhEt.

Publication types

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

MeSH terms

  • Alkenes / chemistry*
  • Alkynes / chemistry*
  • Aniline Compounds / chemistry*
  • Catalysis
  • Coordination Complexes / chemical synthesis*
  • Coordination Complexes / chemistry
  • Copper / chemistry*
  • Crystallography, X-Ray
  • Heterocyclic Compounds / chemical synthesis*
  • Heterocyclic Compounds / chemistry
  • Hydrogenation
  • Molecular Structure
  • Stereoisomerism
  • Toluidines / chemistry*

Substances

  • Alkenes
  • Alkynes
  • Aniline Compounds
  • Coordination Complexes
  • Heterocyclic Compounds
  • Toluidines
  • Copper