Department of Chemistry, National Institute of Technology Patna, Patna, 800005, India.
Department of Chemistry, Indian Institute of Technology Patna, Patna, 801106, India.
Chem Asian J. 2022 Feb 1;17(3):e202101156. doi: 10.1002/asia.202101156. Epub 2021 Dec 30.
Inner sphere Tsuji-Trost reaction has found recent application for β-selective Ferrier rearrangement of glycal substrates with alcohol nucleophiles. Herein, we report an efficient and stereoselective synthesis of 2,3-dideoxy-β-O-glycosides from C3-(o-cyanobenzoate) ester protected glycal donors via Ferrier rearrangement under Pd(0)-catalyzed Tsuji-Trost conditions. The synthesized donors indeed reacted with a variety of acceptors to afford the corresponding glycosides in good yields and excellent β-stereoselectivity. The stereochemical outcome of the reactions has been found to be independent of the nature of protecting groups or conformational flexibility of the glycal donors. Furthermore, regeneration of ortho-cyanobenzoic acid post rearrangement makes it a recyclable and reusable stereodirecting group. A preliminary mechanistic study demonstrates the importance of cyano-group for the observed rearrangement and stereoselectivity. Incorporation of the directing group on the benzoate ester has altered the reactivity of the ester group as a leaving group for Tsuji-Trost as well as Ferrier Rearrangement pathway.
内球 Tsuji-Trost 反应最近已应用于糖醛底物与醇亲核试剂的β-选择性 Ferrier 重排。在此，我们报告了一种通过 Pd(0)催化的 Tsuji-Trost 条件下的 Ferrier 重排，从 C3-(邻氰基苯甲酸酯)酯保护的糖醛供体高效立体选择性合成 2,3-二脱氧-β-O-糖苷的方法。合成的供体确实与各种受体反应，以良好的产率和优异的β立体选择性得到相应的糖苷。反应的立体化学结果与保护基的性质或糖醛供体的构象灵活性无关。此外，重排后邻氰基苯甲酸的再生使其成为可回收和可重复使用的立体定向基团。初步的机理研究表明，氰基对观察到的重排和立体选择性很重要。在苯甲酸酯上引入导向基团改变了酯基作为 Tsuji-Trost 和 Ferrier 重排途径的离去基团的反应性。
