Iridium-catalyzed C-C coupling via transfer hydrogenation: carbonyl addition from the alcohol or aldehyde oxidation level employing 1,3-cyclohexadiene

Org Lett. 2008 Mar 6;10(5):1033-5. doi: 10.1021/ol800159w. Epub 2008 Feb 7.

Abstract

Under hydrogen autotransfer conditions employing a catalyst derived from [Ir(cod)Cl]2 and BIPHEP, 1,3-cyclohexadiene (CHD) couples to benzylic alcohols 1a-9a to furnish carbonyl addition products 1c-9c, which appear as single diastereomers with variable quantities of regioisomeric adducts 1d-9d. Under related transfer hydrogenation conditions employing isopropanol as terminal reductant, identical carbonyl adducts 1c-9c are obtained from the aldehyde oxidation level. Isotopic labeling studies corroborate a mechanism involving hydrogen donation from the reactant alcohol or sacrificial alcohol (i-PrOH).

Publication types

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

MeSH terms

  • Alcohols / chemistry
  • Aldehydes / chemistry
  • Catalysis
  • Cyclohexenes / chemistry*
  • Hydrogenation
  • Iridium / chemistry*
  • Ketones / chemistry*
  • Molecular Structure
  • Oxidation-Reduction
  • Stereoisomerism

Substances

  • Alcohols
  • Aldehydes
  • Cyclohexenes
  • Ketones
  • Iridium
  • 1,3-cyclohexadiene