title: Generating Active "L-Pd(0)" via Neutral or Cationic π-Allylpalladium Complexes Featuring Biaryl/Bipyrazolylphosphines: Synthetic, Mechanistic, and Structure-Activity Studies in Challenging Cross-Coupling Reactions.
abstract: Two new classes of highly active yet air- and moisture-stable π-R-allylpalladium complexes containing bulky biaryl- and bipyrazolylphosphines with extremely broad ligand scope have been developed. Neutral π-allylpalladium complexes incorporated a range of biaryl/bipyrazolylphosphine ligands, while extremely bulky ligands were accommodated by a cationic scaffold. These complexes are easily activated under mild conditions and are efficient for a wide array of challenging C-C and C-X (X = heteroatom) cross-coupling reactions. Their high activity is correlated to their facile activation to a 12-electron-based "L-Pd(0)" catalyst under commonly employed conditions for cross-coupling reactions, noninhibitory byproduct release upon activation, and suppression of the off-cycle pathway to form dinuclear (μ-allyl)(μ-Cl)Pd2(L)2 species, supported by structural (single crystal X-ray) and kinetic studies. A broad scope of C-C and C-X coupling reactions with low catalyst loadings and short reaction times highlight the versatility and practicality of these catalysts in organic synthesis.
authors.affiliation: Johnson Matthey Catalysis and Chiral Technologies, 2001 Nolte Drive, West Deptford, New Jersey 08066, United States.
authors.forename: A J
authors.initials: AJ
authors.lastname: DeAngelis
authors.affiliation: Johnson Matthey Catalysis and Chiral Technologies, 2001 Nolte Drive, West Deptford, New Jersey 08066, United States.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Gildner
authors.affiliation: Johnson Matthey Catalysis and Chiral Technologies, 2001 Nolte Drive, West Deptford, New Jersey 08066, United States.
authors.forename: Ruishan
authors.initials: R
authors.lastname: Chow
authors.affiliation: Johnson Matthey Catalysis and Chiral Technologies, 2001 Nolte Drive, West Deptford, New Jersey 08066, United States.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Colacot