A general method for the asymmetric synthesis of both enantiomers of 1-substituted 1,2,3,4-tetrahydro-β-carbolines employing pyroglutamic acid derivatives as chiral auxiliaries
作者:Takashi Itoh、Michiko Miyazaki、Sachiko Ikeda、Kazuhiro Nagata、Masashi Yokoya、Yuji Matsuya、Yasuko Enomoto、Akio Ohsawa
DOI:10.1016/s0040-4020(03)00420-4
日期:2003.5
9-(S)-Pyroglutaminyl-beta-carbolines were allowed to react with a nucleophile (allyltributyltin or a silyl enol ether) in the presence of 2,2,2-trichloroethyl chloroformate to give 1,2-addition products in good yields and high diastereoselectivity. The chiral auxiliary at N-9 was readily removed by a mild hydrolysis. The same chiral source afforded both enantiomers by simply altering a protecting group of the amide nitrogen. That is, (S)-pyroglutaminyl groups which had an N-alkyl group afforded the (S) isomer, whereas the ones having an N-acyl group produced the (R) isomer of the addition products. (C) 2003 Elsevier Science Ltd. All rights reserved.