Structural studies of peri-interactions and bond formation between electron-rich atomic centres and N-phenylcarboxamides or nitroalkenyl groups
作者:Jane O’Leary、Xavier Formosa、Wolfgang Skranc、John D. Wallis
DOI:10.1039/b506045a
日期:——
Structural studies of peri-interactions with dimethylamino groups in naphthalene systems indicate that the N-phenylcarboxamide group has a through-space electron attracting power closer to that of a carboxylic ester than a N,N-dialkylcarboxamide, while 2-nitroalkenyl groups have a lower through-space electron attracting power. However, addition of a benzoyl group to the 2-position of the nitroethenyl group leads to cyclisation to give a zwitterion, in which the carbanion is stabilised by full conjugation with the nitro group and partial conjugation with the carbonyl group. An interesting case where a steric interaction overrides an electrophile/nucleophile attraction is also described. The limitations to the interpretation of short contact distances from crystallographic measurements are discussed.
萘体系中与二甲氨基的周边相互作用的结构研究表明,N-苯基甲酰胺基团的穿过空间电子吸引能力比 N,N-二烷基甲酰胺更接近于羧酸酯,而 2-硝基烯基的穿过空间电子吸引能力较低。穿过空间的电子吸引力。然而,将苯甲酰基加成至硝基乙烯基的2-位导致环化产生两性离子,其中碳负离子通过与硝基的完全共轭和与羰基的部分共轭而稳定。还描述了一个有趣的案例,其中空间相互作用超越亲电/亲核吸引力。讨论了晶体学测量解释短接触距离的局限性。