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.
J Am Chem Soc. 2015 Dec 16;137(49):15518-27. doi: 10.1021/jacs.5b10466. Epub 2015 Dec 3.
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.
在这里，我们描述了铑（I）催化的、双官能团配体辅助的酮 α-C-H 烯丙基化反应的详细研究，使用了内部炔烃。通过控制反应条件，可以选择性地得到共轭烯胺、α,β-或β,γ-不饱和酮。芳基和脂肪族炔烃都可以作为偶联试剂。该反应条件还能耐受广泛的官能团，包括羧酸酯、丙二酸酯、仲酰胺、硫醚和游离醇。此外，在形成α,β-不饱和酮产物时，四取代烯烃表现出优异的 E-选择性。通过控制实验、动力学监测、合成铑-氢化物中间体及其与炔烃的反应、氘标记实验以及催化剂的静止状态鉴定，对该转化的机理进行了探索。
