Herein, we report an efficient, stereoselective synthesis of 2,3-unsaturated glycosides under mild conditions through a novel Ferrier rearrangement of reasonably designed glycal donors with C3-position ortho-2,2-dimethoxycarbonycyclopropylbenzoyl (CCBz), facilitated by user-friendly, eco- and environmental-friendly Cu(OTf)₂ or Fe(OTf)₃. The newly devised rearrangement tactic is highly α-stereoselective and applies to a broad scope of nucleophile acceptors, enabling the construction of 2,3-unsaturated O-, S-, N-, and C-glycosides, with exceptional yields and stereoselectivities. DFT calculations were conducted to elucidate the reaction mechanism, unveiling the dual role of the metal catalysts in activating the glycal donor through promoting ring-opening of the intramolecularly incorporated donor–acceptor cyclopropane (DAC) of CCBz and directing the following α-face-preferential nucleophilic attack of the incoming acceptor mediated by H-bond interactions.

中文翻译：

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立体选择性应变释放费里尔重排：催化剂的双重作用


在此，我们报告了在温和条件下，通过合理设计的糖基供体与C3位邻-2,2-二甲氧基羰基环丙基苯甲酰基（CCBz）的新型费里尔重排，在用户友好的促进下，高效、立体选择性地合成2,3-不饱和糖苷。生态环保的Cu(OTf) ₂ 或Fe(OTf) ₃ 。新设计的重排策略具有高度的α-立体选择性，适用于广泛的亲核受体，能够构建2,3-不饱和O-、S-、N-和C-糖苷，具有优异的产率和立体选择性。通过DFT计算阐明了反应机理，揭示了金属催化剂通过促进CCBz分子内结合的供体-受体环丙烷（DAC）开环来激活糖醛供体的双重作用，并指导以下α-面优先反应由氢键相互作用介导的传入受体的亲核攻击。