蒽酮与β-硝基苯乙烯的不对称Michael加成反应

Enantioselective Organocatalytic Michael Addition of Anthrone to Nitroalkenes

不对称催化Michael加成反应是一类重要的形成碳—碳键的反应,以蒽酮作为亲核试剂的不对称Michael反应报道甚少.以手性伯胺硫脲作为催化剂,对蒽酮与硝基苯乙烯的不对称有机催化Michael加成反应进行了研究.实验结果表明,所用的伯胺硫脲均具有较好的催化活性(80%～95%收率),其中硫脲4a得到了较高的对映选择性.对反应条件进行优化后,以乙醚为溶剂,使用5%摩尔分数催化剂4a和苯甲酸,研究了多个硝基苯乙烯类底物和蒽酮的Michael加成反应,获得了优异的化学收率(95%～98%)和较好的对映选择性(最高86%ee).

The enantioselective organocatalytic Michael addition of anthrone to nitroalkenes was investigated using chiral primary amine thiourea. All the screened thioureas based on （1R,2R）-1,2-diphenylethane-1,2-diamine could promote the reaction between anthrone and β-nitrostyrene （80%～95% yields）,and the thiourea 4a afforded good enantioselectivity. Treatment of anthrone with different β-nitrostyrenes in the presence of 5 mol% organocatalyst 4a and 5 mol% benzoic acid in ether provided the desired Michael products with excellent chemical yields （95%～98% yields） and good enantioselectivities （up to 86% ee）.