Dual reactivity pattern of allenolates "on water": the chemical basis for efficient allenolate-driven organocatalytic systems

Chemistry. 2007;13(17):4823-32. doi: 10.1002/chem.200700227.

Abstract

A study of the reactivity pattern associated with zwitterionic allenolates "on water" is reported. This study establishes the chemical basis for two organocatalyzed allenolate-driven reaction networks operating "on water". The first one is a chemodifferentiating three building block (ABB') three-component reaction (ABB' 3CR) manifold comprising terminal alkynoates and aldehydes. The manifold produces propargylic enol ethers 3 with higher average efficiency than their homologues in organic solvents. The second one is a novel organocatalytic system elicited by the reaction of alkynoates and nitrones in the presence of tertiary amines or phosphines. While terminal alkynoates afford 2,3,5-trisubstituted 2,3-dihydroisoxazoles 5 and propargylic N-hydroxylamines 6, internal alkynoates selectively afford the 2,3,4,5-tetrasusbstituted 2,3-dihydroisoxazaole 10. Importantly, in both cases, the 2,3-dihydroisoxazole ring is obtained as a sole regioisomer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkynes / chemistry
  • Catalysis
  • Naphthalenes / chemistry*
  • Nitrogen Oxides / chemistry
  • Stereoisomerism
  • Water / chemistry*

Substances

  • Alkynes
  • Naphthalenes
  • Nitrogen Oxides
  • nitrones
  • Water
  • allenolic acid