Lewis Acids Accelerate Reductive Elimination of RCN from P₂Pd(R)(CN)

Abstract

The rate of reductive elimination of the complexes dpppPd(CH2TMS)(CNER3) (E = B, Al) is accelerated up to 60-fold over dpppPd(CH2TMS)(CN). Based on kinetic considerations and the isoelectronic relationship of CN- and CO, a migration-type mechanism for reductive elimination is proposed. The rate acceleration correlates directly with Lewis acid strength, the latter determined by solution calorimetric analyses of the Lewis acid adduct forming reaction Pd−CN + ER3 → Pd−CN−ER3.