P-C bond activation chemistry: evidence for 1,1-carboboration reactions proceeding with phosphorus-carbon bond cleavage

J Am Chem Soc. 2011 Mar 30;133(12):4610-6. doi: 10.1021/ja1110283. Epub 2011 Mar 2.

Abstract

A series of diarylphosphinyl-substituted acetylenes of the type (aryl)(2)P-C≡C-R (aryl = phenyl or mesityl, R = Ph or n-propyl) react with the strongly Lewis acid reagent B(C(6)F(5))(3) in toluene at elevated temperatures (70-105 °C) to give the 1,1-carboboration products 4. Treatment of bis(diphenylphosphinyl)acetylene with B(C(6)F(5))(3) under analogous conditions proceeded with phosphinyl migration to yield the 1,1-carboboration product 4d, bearing a geminal pair of Ph(2)P substituents at one former acetylene carbon atom and a C(6)F(5) substituent and the remaining -B(C(6)F(5))(2) group at the other. Prolonged thermolysis of 4d resulted in an intramolecular aromatic substitution reaction by means of Ph(2)P attack on the adjacent C(6)F(5) ring to yield the zwitterionic phospha-indene derivative 7. The compounds 4a, 4c, 4d, and 7 were characterized by X-ray diffraction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylene / chemistry
  • Boron Compounds / chemical synthesis
  • Boron Compounds / chemistry
  • Carbon / chemistry*
  • Crystallography, X-Ray
  • Models, Molecular
  • Molecular Structure
  • Organophosphorus Compounds / chemical synthesis
  • Organophosphorus Compounds / chemistry*
  • Phosphorus / chemistry*

Substances

  • Boron Compounds
  • Organophosphorus Compounds
  • Phosphorus
  • Carbon
  • Acetylene