title: Highly active palladium catalysts supported by bulky proazaphosphatrane ligands for Stille cross-coupling: coupling of aryl and vinyl chlorides, room temperature coupling of aryl bromides, coupling of aryl triflates, and synthesis of sterically hindered biaryls.
abstract: A family of proazaphosphatrane ligands [P(RNCH2CH2)2N(R'NCH2CH2): R = R' = i-Bu, 1; R = Bz, R' = i-Bu, 3; R = R' = Bz, 4] for palladium-catalyzed Stille reactions of aryl chlorides is described. Catalysts derived from ligands 1 and 4 efficiently catalyze the coupling of electronically diverse aryl chlorides with an array of organotin reagents. The catalyst system based on the ligand 3 is active for the synthesis of sterically hindered biaryls (di-, tri-, and tetra-ortho substituted). The use of ligand 4 allows room-temperature coupling of aryl bromides and it also permits aryl triflates and vinyl chlorides to participate in Stille coupling.
authors.affiliation: Department of Chemistry, Gilman Hall, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Weiping
authors.initials: W
authors.lastname: Su
authors.forename: Sameer
authors.initials: S
authors.lastname: Urgaonkar
authors.forename: Patrick A
authors.initials: PA
authors.lastname: McLaughlin
authors.forename: John G
authors.initials: JG
authors.lastname: Verkade