Linking borane with N-heterocyclic carbenes: effective hydrogen-atom donors for radical reactions.
Undue influence: N-heterocyclic carbenes (NHCs) were found to reduce the strength of the B-H bonds of borane by a surprisingly large amount upon the formation of NHC-BH(3) complexes. This property was exploited in the development of a suite of NHC-borane complexes for the reduction of xanthates in radical-mediated Barton-McCombie-type deoxygenation reactions (see scheme). AIBN = azobisisobutyronitrile, Bn = benzyl.
Walton
John C
JC
School of Chemistry, University of St. Andrews, St. Andrews, Fife, KY16 9ST, UK. jcw@st-and.ac.uk