Steric and Electronic Effects in the Synthesis and Regioselective Hydrolysis of Unsymmetrical Imides
作者:Jing Shang、Aysa Pourvali、James R. Cochrane、Craig A. Hutton
DOI:10.1071/ch15504
日期:——
pivalic acid) are tolerated, but electron deficient acids, such as trifluoroacetic acid, are ineffective coupling partners. Furthermore, an interplay of both steric and electronic effects is observed in the subsequent hydrolysis of unsymmetrical imides. Imides with a dimethoxybenzoyl group give high regioselectivity upon hydrolysis, favouring cleavage of the distal acyl group. Imides with a p-nitrobenzoyl
银我硫代酰胺和羧酸的α-促进的偶合反应被证明是产生不对称酰亚胺的有用方法。该反应在不受阻碍且富含电子或中性的偶合伙伴的条件下有效地进行,但与受阻的硫代酰胺(如硫代新戊酰胺)或电子不足的硫代酰胺(如三氟硫代乙酰胺)无效。有趣的是,尽管空间或电子影响最小,但硫代甲酰胺还是无效的偶联伴侣。可以阻止受阻的羧酸偶合剂(如新戊酸),但缺电子的酸(如三氟乙酸)则无效。此外,在随后的不对称酰亚胺的水解中观察到空间效应和电子效应的相互作用。具有二甲氧基苯甲酰基的酰亚胺在水解时具有高的区域选择性,有利于远端酰基的裂解。酰亚胺与对硝基苯甲酰基或新戊酰基具有相反的选择性,有助于裂解近端酰基。