Enantioselective Synthesis of Pyroglutamic Acid Esters from Glycinate via Carbonyl Catalysis
作者:Jiguo Ma、Qinghai Zhou、Guanshui Song、Yongchang Song、Guoqing Zhao、Kuiling Ding、Baoguo Zhao
DOI:10.1002/anie.202017306
日期:2021.5.3
Direct α‐functionalization of NH2‐free glycinates with relatively weak electrophiles such as α,β‐unsaturated esters still remains a big challenge in organic synthesis. With chiral pyridoxal 5 d as a carbonyl catalyst, direct asymmetric conjugated addition at the α‐C of glycinate 1 a with α,β‐unsaturated esters 2 has been successfully realized, to produce various chiral pyroglutamic acid esters 4 in 14–96 %
用相对较弱的亲电试剂(例如,α,β-不饱和酯)将不含NH 2的甘氨酸直接进行α-官能化仍然是有机合成中的一大挑战。以手性吡ido醛5 d作为羰基催化剂,已成功实现在甘氨酸1a的α-C与α,β-不饱和酯2的直接不对称共轭加成反应,以14-96%的收率生产各种手性焦谷氨酸酯4原位内酰胺化后具有81–97%ee的物质。该反式与顺非对映异构体可以通过色谱法同时获得,并且可以很容易地通过叔丁基去除和随后的Barton转化为手性4取代的吡咯烷-2-酮,例如具有相同绝对构型的阿兹海默氏药物Rolipram(11)。脱羧。