作者:Alan R. Bassindale、Patricia A. Kyle、Marie-Claire Soobramanien、Peter G. Taylor
DOI:10.1039/a906233e
日期:——
2-Trialkylsilylaziridines do not readily undergo nucleophilic ring opening without electrophilic assistance. In the presence of strong acids protonation at the nitrogen is followed by nucleophilic attack α to the silicon. With non-nucleophilic counterions, the protonated aziridine can be obtained. N-Alkylation gives the aziridinium salt, which also undergoes α-cleavage. However, the presence of a 3-phenyl substituent gives a stable aziridinium salt that undergoes nucleophilic attack β to the silicon. Reaction of 2-trialkylsilylaziridines with trialkylsilyl halides usually leads to α-cleavage, however, desilylation to give the enamine is also observed. Fluorodesilylation of the 2-trialkylsilylaziridine is not straightforward and only occurred readily when a 2-ethoxycarbonyl group was present. Fluorodesilylation followed by attack on a carbonyl was only observed when very dry samples of fluoride ions were employed.
2-Trialkylsilylaziridines 在没有亲电援助的情况下不易发生亲核开环。在强酸存在的情况下,氮发生质子化反应,随后硅发生亲核反应 α。在非亲核反离子的作用下,可以得到质子化的氮丙啶。通过 N-烷基化可得到氮丙啶鎓盐,它也会发生 α 裂解。然而,3-苯基取代基的存在会产生一种稳定的氮丙啶鎓盐,这种盐会对硅进行β亲核反应。2-三烷基硅烷氮丙啶与三烷基硅烷卤化物的反应通常会导致 α 裂解,但也会出现脱硅反应,生成烯胺。2-三烷基甲硅烷基氮丙啶的氟代脱水作用并不简单,只有在存在 2-乙氧基羰基时才容易发生。只有在使用非常干燥的氟离子样品时,才会观察到氟代甲硅烷基化反应,然后攻击羰基。