Mechanistic Insights into C(sp2 )-C(sp)N Reductive Elimination from Gold(III) Cyanide Complexes.

A new family of phosphine-ligated dicyanoarylgold(III) complexes has been prepared and their reactivity towards reductive elimination has been studied in detail. Both, a highly positive entropy of activation and a primary 12/13 C KIE suggest a late concerted transition state while Hammett analysis and DFT calculations indicate that the process is asynchronous. As a result, a distinct mechanism involving an asynchronous concerted reductive elimination for the overall C(sp2 )-C(sp)N bond forming reaction is characterized herein, for the first time, complementing previous studies reported for C(sp3 )-C(sp3 ), C(sp2 )-C(sp2 ), and C(sp3 )-C(sp2 ) bond formation processes taking place on gold(III) species.