Sobhani Sara, Fielenbach Doris, Marigo Mauro, Wabnitz Tobias C, Jørgensen Karl Anker
Danish National Research Foundation, Center for Catalysis, Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark.
Chemistry. 2005 Sep 19;11(19):5689-94. doi: 10.1002/chem.200500512.
The application of cinchona alkaloid derivatives as catalysts for enantioselective alpha-sulfenylation of activated C-H bonds in lactones, lactams, and beta-dicarbonyl compounds by different electrophilic sulfur reagents is presented. Optically active products are obtained in good to excellent yields and up to 91 % ee. Furthermore, the diastereoselective reduction of alpha-sulfenylated beta-keto esters to give optically active alpha-sulfenylated beta-hydroxy esters has been studied. A model for the intermediate is presented, in which the protonated cinchona alkaloid interacts with the substrate leading to face-shielding in accordance with the enantioselective alpha-sulfenylation step.
本文介绍了金鸡纳生物碱衍生物作为催化剂，用于内酯、内酰胺和β-二羰基化合物中活性C-H键通过不同亲电硫试剂进行对映选择性α-硫代化反应。可获得光学活性产物，产率良好至优异，对映体过量率高达91%。此外，还研究了α-硫代化β-酮酯的非对映选择性还原反应，以得到光学活性的α-硫代化β-羟基酯。提出了一个中间体模型，其中质子化的金鸡纳生物碱与底物相互作用，根据对映选择性α-硫代化步骤导致面屏蔽。
