Mechanistic studies of Pd-catalyzed regioselective aryl C-H bond functionalization with strained alkenes: origin of regioselectivity

Chemistry. 2011 Jul 11;17(29):8175-88. doi: 10.1002/chem.201100210. Epub 2011 Jun 3.

Abstract

Mechanistic studies of a palladium-catalyzed regioselective aryl C-H functionalization of 2-pyrrole phenyl iodide with norbornene are presented. Kinetic and spectroscopic analyses together with crystallographic data provide evidence for intermediates in a proposed stepwise mechanism. On the basis of the mechanistic studies, the origin of the regioselectivity is due to a ligand exchange between I(-) and HO(-) on the norbornyl palladium complex. These mechanistic studies also implicate that either alkoxide or water is responsible for the formation of the palladacycle, but a reversible ring-opening-ring-closing process of the palladacycle with HX can retard the rate of reaction of a key intermediate. The significant aspects of the proposed mechanism are discussed in detail.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkenes / chemistry*
  • Catalysis
  • Crystallography, X-Ray
  • Iodides / chemistry
  • Models, Molecular
  • Norbornanes / chemistry*
  • Palladium / chemistry*
  • Pyrroles / chemistry
  • Stereoisomerism
  • Water / chemistry

Substances

  • Alkenes
  • Iodides
  • Norbornanes
  • Pyrroles
  • Water
  • Palladium