A route to Pd0 from Pd(II) metallacycles in amination and cross- coupling chemistry

Article abstract of DOI:10.1002/anie.199623591

Pd(II)/Pd(IV) or Pd(II)/Pd⁰? The unusual Pd(II) 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 elimination generate a coordinate 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 Pd(II)/Pd⁰-containing catalytic cycle.