851512-46-4Relevant academic research and scientific papers
Asymmetric induction in the conjugate addition of thioacetic acid to methacrylamides with chiral auxiliaries
Kim, Byung Hyun,Lee, Hee Bong,Hwang, Jae Kwang,Kim, Young Gyu
, p. 1215 - 1220 (2005)
The conjugate addition of thioacetic acid to methacrylamides with chiral C2-symmetric trans-2,5-disubstituted pyrrolidines afforded the addition products in excellent stereoselectivities (>99% de) and good yields (80-90%). The high selectivity was attributed mainly to the steric effect of the chiral auxiliaries. The cyclic nature of the chiral auxiliaries seemed also important for both the stereoselectivity and the reaction rate. Acidic hydrolysis of the adduct containing (2R,5R)-bis(methoxymethyl)pyrrolidine gave (S)-3-mercapto-2-methylpropanoic acid, a key intermediate for captopril, in 98% ee and 96% yield. The chiral auxiliary was recovered in the demethylated form of N-Boc-(2R,3R)-bis(hydroxymethyl)pyrrolidine in 90% yield.
