title: Probing electronic effects in the asymmetric Heck reaction with the BIPI ligands.
abstract: [structure: see text] The new BIPI ligands are phosphinoimidazolines that can be electronically tuned in three different ligand regions to explore electronic effects in asymmetric catalysis. Their application to the asymmetric Heck reaction (AHR) in the creation of a chiral quaternary center is described. Enantioselectivity is shown for the first time to depend linearly on phosphine electron density. Changing the ligand basicity by variation of the R(2) or R(3) substituents reverses facial selectivity.
authors.affiliation: Department of Chemical Development, Boehringer-Ingelheim Pharmaceuticals, Inc., 900 Ridgebury Rd., Ridgefield, Connecticut 06877, USA. cbusacca@rdg.boehringer-ingelheim.com
authors.forename: Carl A
authors.initials: CA
authors.lastname: Busacca
authors.forename: Danja
authors.initials: D
authors.lastname: Grossbach
authors.forename: Regina C
authors.initials: RC
authors.lastname: So
authors.forename: Erin M
authors.initials: EM
authors.lastname: O'Brien
authors.forename: Earl M
authors.initials: EM
authors.lastname: Spinelli
mesh_terms: D002384:Catalysis; D004583:Electrons; D007093:Imidazoles / Q000737:chemistry*; D008024:Ligands; D010720:Phosphines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D007093:Imidazoles; D008024:Ligands; D010720:Phosphines