Controlling chemoselective transformations of 4-acylpyridines via a Pd–C catalytic hydrodechlorination–hydrogenation
摘要:
A novel Pd-C catalytic hydrodechlorination-hydrogenation was developed for a multi-step one-pot transformation of 4-acylpyridines. Under the selected conditions, 4-benzoylpyridines and 4-alkanoylpyridines were chemoselectively converted into the corresponding 4-benzylpiperidine hydrochlorides and alpha-alkyl-4-piperidinemethanol hydrochlorides, respectively. This catalytic method was performed simply by an addition of 1 equiv of CICH2CHCl2 to the conventional hydrogenation system and directly gave the crystalline piperidine hydrochlorides in practical quantitative yields. (C) 2013 Elsevier Ltd. All rights reserved.