Complexes of borane and N-heterocyclic carbenes: a new class of radical hydrogen atom donor

Shau-Hua Ueng; Malika Makhlouf Brahmi; Etienne Derat; Louis Fensterbank; Emmanuel Lacôte; Max Malacria; Dennis P Curran

doi:10.1021/ja804150k

Complexes of borane and N-heterocyclic carbenes: a new class of radical hydrogen atom donor

J Am Chem Soc. 2008 Aug 6;130(31):10082-3. doi: 10.1021/ja804150k. Epub 2008 Jul 9.

Authors

Shau-Hua Ueng¹, Malika Makhlouf Brahmi, Etienne Derat, Louis Fensterbank, Emmanuel Lacôte, Max Malacria, Dennis P Curran

Affiliation

¹ Institut de chimie moléculaire (FR 2769), Laboratoire de chimie organique (UMR CNRS 7611), UPMC Univ Paris 06, C. 229, 4 place Jussieu, 75005 Paris, France.

PMID: 18611014
DOI: 10.1021/ja804150k

Abstract

Calculations suggest that complexes of borane with N-heterocyclic carbenes (NHC) have B-H bond dissocation energies more then 20 kcal/mol less than free borane, diborane, borane-THF, and related complexes. Values are in the range of popular radical hydrogen atom donors like tin hydrides (70-80 kcal/mol). The resulting prediction that NHC borane complexes could be used as radical hydrogen atom donors was verified by radical deoxygenations of xanthates by using either AIBN or triethylborane as initiator.