title: Bifunctional Ligand-Assisted Catalytic Ketone α-Alkenylation with Internal Alkynes: Controlled Synthesis of Enones and Mechanistic Studies.
abstract: Here, we describe a detailed study of the rhodium(I)-catalyzed, bifunctional ligand-assisted ketone α-C-H alkenylation using internal alkynes. Through controlling the reaction conditions, conjugated enamines, α,β- or β,γ-unsaturated ketones, can be selectively accessed. Both aromatic and aliphatic alkynes can be employed as coupling partners. The reaction conditions also tolerate a broad range of functional groups, including carboxylic esters, malonates, secondary amides, thioethers, and free alcohols. In addition, excellent E-selectivity was observed for the tetra-substituted alkene when forming the α,β-unsaturated ketone products. The mechanism of this transformation was explored through control experiments, kinetic monitoring, synthesizing the rhodium-hydride intermediates and their reactions with alkynes, deuterium-labeling experiments, and identification of the resting states of the catalyst.
authors.affiliation: Department of Chemistry, University of Texas at Austin , Austin, Texas 78712, United States.|Department of Energy and Resources Engineering, College of Engineering, Peking University , Beijing 100871, China.
authors.forename: Fanyang
authors.initials: F
authors.lastname: Mo
authors.affiliation: Department of Chemistry, University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Hee Nam
authors.initials: HN
authors.lastname: Lim
authors.affiliation: Department of Chemistry, University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Guangbin
authors.initials: G
authors.lastname: Dong