Direct Organocatalytic Asymmetric α-Sulfenylation of Activated CH Bonds in Lactones, Lactams, and β-Dicarbonyl Compounds
作者:Sara Sobhani、Doris Fielenbach、Mauro Marigo、Tobias C. Wabnitz、Karl Anker Jørgensen
DOI:10.1002/chem.200500512
日期:2005.9.19
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
提出了金鸡纳生物碱衍生物作为催化剂通过不同的亲电硫试剂对内酯,内酰胺和β-二羰基化合物中的活化CH键进行对映选择性α-亚磺酰基化的应用。以良好至优异的产率和高达91%ee获得光学活性产物。此外,已经研究了α-亚磺酰基化的β-酮酯的非对映选择性还原,以产生光学活性的α-亚磺酰基化的β-羟基酯。提出了中间体的模型,其中质子化的金鸡纳生物碱与底物相互作用,从而根据对映选择性的α-亚磺酰基化步骤进行了遮盖。