A Route to Pd^o from Pd^II Metallacycles in Animation and Cross‐Coupling Chemistry

PdII/PdIV or PdII/Pd0? The unusual PdII catalyst 1 was reduced to a Pd0 complex by reaction with an amine and a base. β-Hydrogen elimination and subsequent CH bond-forming reductive elmination generate a coordinated tris(o-tolyl)phosphane. The same palladium(II) metallacycle was reduced to Pd0 in a cross-coupling reaction by CC bond-forming reductive elimination to form coordinated P(oTol)2-(C6H4CH2Ar). Thus, these compounds can react by a PdII/Pd0-containing catalytic cycle.