Cascade reactions: a new synthesis of 2-benzofuran-2-ylacetamides by sequential Pd(0)-catalyzed deallylation-Pd(II)-catalyzed aminocarbonylative heterocyclization of 1-(2-allyloxyaryl)-2-yn-1-ols

J Org Chem. 2007 Nov 23;72(24):9278-82. doi: 10.1021/jo701956k. Epub 2007 Nov 1.

Abstract

A general and efficient synthesis of 2-benzofuran-2-ylacetamides 5 starting from 1-(2-allyloxyaryl)-2-yn-1-ols 1, amines 4, and CO, in the presence of catalytic amounts of PdI2 in conjunction with PPh3 and KI, has been developed based on the "sequential homobimetallic catalysis" concept, that is, a process in which two different complexes of the same metal, but in two different oxidation states, promote two catalytic cycles in sequence. The first cycle corresponds to a Pd(0)-catalyzed aminodeallylation of 1 with formation of the free phenol 2, which then undergoes Pd(II)-catalyzed aminocarbonylative heterocyclization to give the final product 5.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetamides / chemistry*
  • Allyl Compounds / chemistry*
  • Amines / chemistry*
  • Benzofurans / chemistry*
  • Catalysis
  • Cyclization
  • Models, Chemical
  • Palladium / chemistry*
  • Stereoisomerism

Substances

  • Acetamides
  • Allyl Compounds
  • Amines
  • Benzofurans
  • Palladium