The chiral unsymmetrical α,α-diarylmethine skeleton is widely found in natural products and synthetic pharmaceuticals. The catalytic asymmetric C–H insertion reaction of simple, unprotected indoles and pyrroles with α-aryl sulfur ylides provides a direct route to their stereoselective preparation. Nevertheless, controlling the reactivity and stereoselectivity of this reaction has presented a significant challenge. In this study, we present the highly enantioselective asymmetric formal C–H insertion reactions of N–H free indoles and pyrroles with sulfoxonium ylides, yielding chiral gem-heterodiarylmethine frameworks with good to excellent yields and enantioselectivities. Importantly, experimental mechanistic studies and DFT calculations indicate that the stereoselectivity originates from dynamic kinetic resolution, where multiple noncovalent interactions play a pivotal role, with C–C bond formation as the rate-determining step. The findings in this study may pave the way for the development of catalytic asymmetric C–H insertion reactions of sulfur ylides with other carbon nucleophiles.

中文翻译：

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通过亚砜叶立德与吲哚和吡咯的有机催化形式 C-H 插入反应对映选择性合成不对称 α,α-二芳基乙酸酯


手性不对称α,α-二芳基次甲基骨架广泛存在于天然产物和合成药物中。简单的、未保护的吲哚和吡咯与α-芳基硫叶立德的催化不对称C-H插入反应为它们的立体选择性制备提供了直接途径。然而，控制该反应的反应性和立体选择性提出了重大挑战。在这项研究中，我们提出了N-H游离吲哚和吡咯与亚砜叶立德的高度对映选择性不对称形式C-H插入反应，产生了具有良好至优异产率和对映选择性的手性宝石-杂二芳基次甲基骨架。重要的是，实验机理研究和 DFT 计算表明，立体选择性源自动态动力学分辨率，其中多种非共价相互作用发挥着关键作用，其中 C-C 键形成是速率决定步骤。这项研究的结果可能为硫叶立德与其他碳亲核试剂的催化不对称C-H插入反应的发展铺平道路。