title: Mechanistic Model for Enantioselective Intramolecular Alkene Cyanoamidation via Palladium-Catalyzed C-CN Bond Activation.
abstract: We studied key aspects of the mechanism of Pd-catalyzed C-CN bond activation and intramolecular enantioselective alkene cyanoamidation. An Abboud-Abraham-Kamlet-Taft (AAKT) linear solvation energy relationship (LSER) model for enantioselectivity was established. We investigated the impact of Lewis acid (BPh3), Lewis base (DMPU), and no additives. BPh3additive led to diminished enantioselectivity and differing results in13CN crossover experiments, initial rate kinetics, and natural abundance12C/13C kinetic isotope effect measurements. We propose two catalytic mechanisms to account for our experimental results. We propose that the DMPU/nonadditive pathway passes through a κ2-phosphoramidite-stabilized Pd+intermediate, resulting in high enantioselectivity. BPh3prevents the dissociation of CN-, leading to a less rigid κ2-phosphoramidite-neutral Pd intermediate.
authors.affiliation: Department of Chemistry, University of Minnesota-Twin Cities , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.
authors.forename: Grant B
authors.initials: GB
authors.lastname: Frost
authors.affiliation: Department of Chemistry, University of Minnesota-Twin Cities , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.
authors.forename: Nicholas A
authors.identifier: 0000-0002-2602-425X
authors.initials: NA
authors.lastname: Serratore
authors.affiliation: Department of Chemistry, University of Minnesota-Twin Cities , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.
authors.forename: Jodi M
authors.initials: JM
authors.lastname: Ogilvie
authors.affiliation: Department of Chemistry, University of Minnesota-Twin Cities , 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States.
authors.forename: Christopher J
authors.identifier: 0000-0002-1904-6135
authors.initials: CJ
authors.lastname: Douglas
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000577:Amides / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D002384:Catalysis; D003486:Cyanides / Q000737:chemistry; D007554:Isotopes; D007700:Kinetics; D008956:Models, Chemical; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D000577:Amides; D003486:Cyanides; D007554:Isotopes; D010165:Palladium; D002244:Carbon