(S)-Ethyl 4,4-dimethyl pyroglutamate as a new ‘quat’ chiral auxiliary in aldol condensations
作者:Jesús Ezquerra、Almudena Rubio、Justina Martín、JoséLuis García Navío
DOI:10.1016/s0957-4166(97)00028-1
日期:1997.3
Enolates I, derived from the N-propionyl derivative of the 'quat' chiral auxiliary (S)-ethyl 4,4-dimethyl pyroglutamate 4 undergo highly stereoselective aldol reactions, which upon hydrolysis and removal of the chiral auxiliary yields the (2R,3R)-3-hydroxy-2-methylpropionic acid 9 in homochiral form. Remarkably, the stereogenic center of 4 was not affected during all the chemical transformations and it could be regenerated after the process in 70% yield. (C) 1997 Elsevier Science Ltd.