摘要:
An approach to the synthesis and resolution of five- and six-membered lactams (i.e., 5-oxopyrrolidine-and 6-oxopiperidine-3-carboxylic acids) is described. The method relies on the one-pot Michael reaction-cyclization of itaconic acid or diethyl homoitaconate and enantiopure O-(alpha-phenylethyl) hydroxylamine as a 'chiral ammonia equivalent'. It is shown that this chiral auxiliary can be used for the separation of diastereomeric lactam products and then easily removed by catalytic hydrogenolysis. (C) 2017 Elsevier Ltd. All rights reserved.