The Role of the Alcohol and Carboxylic Acid in Directed Ruthenium-Catalyzed C(sp3)H α-Alkylation of Cyclic Amines
作者:Sheba D. Bergman、Thomas E. Storr、Hana Prokopcová、Karel Aelvoet、Gaston Diels、Lieven Meerpoel、Bert U. W. Maes
DOI:10.1002/chem.201201072
日期:2012.8.13
A general directed Ru‐catalyzed C(sp3)H α‐alkylation protocol for piperidines (less‐reactive substrates than the corresponding five‐membered cyclic amines) has been developed. The use of a hindered alcohol (2,4‐dimethyl‐3‐pentanol) as the solvent and catalyst activator, and a catalytic amount of trans‐1,2‐cyclohexanedicarboxylic acid is necessary to achieve a high conversion to product. This protocol
对于哌啶(反应性底物比相应的五元环胺反应性低的底物),已开发了一种通用的Ru催化的C(sp 3)Hα烷基化方案。使用受阻醇(2,4-二甲基-3-戊醇)作为溶剂和催化剂活化剂,以及催化量的反式为了获得高转化率,必须使用1,2-环己烷二甲酸。该方案用于有效合成许多2-己基和2,6-二己基哌啶,以及生物碱(±)-视紫红质A。动力学研究表明,该羧酸添加剂对催化剂的引发具有显着影响。与无酸反应相比,可延长催化剂寿命,并逆转反应选择性(促进烷基化与竞争性烯烃还原)。