α-Halo Amides as Competent Latent Enolates: Direct Catalytic Asymmetric Mannich-Type Reaction
作者:Bo Sun、Pandur Venkatesan Balaji、Naoya Kumagai、Masakatsu Shibasaki
DOI:10.1021/jacs.7b03291
日期:2017.6.21
dehalogenation and thus largely neglected as enolate precursors in catalytic enantioselective C-C bond-forming reactions. By merging the increased stability of the α-C-halogen bond of amides and the direct enolization methodology of the designed amide, we explored a direct catalytic asymmetric Mannich-type reaction of α-halo 7-azaindoline amides with N-carbamoyl imines. All α-halo substituents, α-F, -Cl, -Br, -I
α-卤代羰基化合物易于脱卤,因此在催化对映选择性 CC 键形成反应中作为烯醇前体在很大程度上被忽视。通过将酰胺的 α-C-卤素键的稳定性提高和设计酰胺的直接烯醇化方法相结合,我们探索了 α-卤代 7-氮杂二氢吲哚酰胺与 N-氨基甲酰基亚胺的直接催化不对称曼尼希型反应。所有 α-卤素取代基,α-F、-Cl、-Br、-I 酰胺都可以耐受,以高度立体选择性的方式提供曼尼希加合物,而不会发生不希望的脱卤。非对映选择性根据芳族亚胺的取代模式发生有趣的变化,这归因于基于开放过渡态模型的立体化学分化。