Camphor-annelated imidazolines with various N1 and C2 pendants as tunable ligands for nitroaldol reactions
作者:Jiří Tydlitát、Filip Bureš、Jiří Kulhánek、Grzegorz Mlostoń、Aleš Růžička
DOI:10.1016/j.tetasy.2012.06.016
日期:2012.7
Starting from (1R,2S,3R)-camphordiamine and (hetero)aromatic imidates and orthoformate, nine new camphor-annelated NH-imidazolines were synthesized. Subsequent N-modification was carried out via methylation, acylation, benzoylation, and sulfonylation. Two regioisomers were usually isolated with the ratios reflecting the structure of the starting NH-imidazoline and the electrophile used. All of the successfully prepared N1- and C2-substituted camphor-annelated imidazolines were applied to the asymmetric version of a Cu(II)-catalyzed Henry reaction. The electronic effects of both N1- and C2-pendants on the chemical and asymmetric outcomes of the nitroaldol reaction have been studied and discussed. (C) 2012 Elsevier Ltd. All rights reserved.