Lebel Hélène, Mamani Laparra Laura, Khalifa Maroua, Trudel Carl, Audubert Clément, Szponarski Mathieu, Dicaire Leduc Cédric, Azek Emna, Ernzerhof Matthias
Department of Chemistry and Centre in Green Chemistry and Catalysis (CGCC), Université de Montréal, Montréal, QC H3C 3J7, Canada.
Org Biomol Chem. 2017 May 16;15(19):4144-4158. doi: 10.1039/c7ob00378a.
N-Mesyloxycarbamates undergo intramolecular C-H amination reactions to afford oxazolidinones in good to excellent yields in the presence of rhodium(ii) carboxylate catalysts. The reaction is performed under green conditions and potassium carbonate is used, forming biodegradable potassium mesylate as a reaction by-product. This method enables the production of electron-rich, electron-deficient, aromatic and heteroaromatic oxazolidinones in good to excellent yields. Conformationally restricted cyclic secondary N-mesyloxycarbamates furnish cis-oxazolidinones in high yields and selectivity; DFT calculations are provided to account for the observed selectivity. trans-Oxazolidinones were prepared from acyclic secondary N-mesyloxycarbamates using Rh(oct). The selectivity was reverted with a cytoxazone N-mesyloxycarbamate precursor using large chiral rhodium(ii) carboxylate complexes, affording the corresponding cis-oxazolidinone. This orthogonal selectivity was used to achieve the formal synthesis of (-)-cytoxazone.
在羧酸铑（II）催化剂存在下，N-甲磺酰氧基氨基甲酸酯发生分子内C-H胺化反应，以良好至优异的产率得到恶唑烷酮。该反应在绿色条件下进行，并使用碳酸钾，形成可生物降解的甲磺酸钾作为反应副产物。该方法能够以良好至优异的产率生产富电子、缺电子、芳香族和杂芳香族恶唑烷酮。构象受限的环状仲N-甲磺酰氧基氨基甲酸酯以高产率和选择性提供顺式恶唑烷酮；提供了DFT计算以解释观察到的选择性。反式恶唑烷酮由无环仲N-甲磺酰氧基氨基甲酸酯使用Rh（辛）制备。使用大的手性羧酸铑（II）配合物，用环嗪酮N-甲磺酰氧基氨基甲酸酯前体使选择性反转，得到相应的顺式恶唑烷酮。这种正交选择性被用于实现（-）-环嗪酮的形式合成。
