Steric control of reactivity: formation of oximes, benzodiazepinone N-oxides and isoxazoloquinolinones
作者:Frances Heaney、Sharon Bourke、Desmond Cunningham、Patrick McArdle
DOI:10.1039/a707857i
日期:——
Reaction of the alkenyl carbonyl compounds 1 with hydroxylamine can lead to the formation of the oximes 2, the benzodiazepinone N-oxides 3 or the isoxazoloquinolinones 5. The product(s) of reaction are shown to depend on the electronic nature of the terminal olefinic substituent R3 and the space filling capacity of the substituents R1, R2 and R4. When the olefinic centre is electron poor (R3 = CO2Et) ketocarbonyls convert exclusively to bicyclic nitrones 3 whereas aldehydes are more sensitive to subtle changes in skeletal structure and give rise to oximes 2, tricycles 5 or mixtures of both. For aldehyde and ketone substrates when the olefinic centre carries an aryl substituent (R3 = Ph) the primary product of reaction is the corresponding oxime which on thermal activation converts to the tricyclic isoxazoloquinolinones.
与氢氧胺反应的烯烃羰基化合物1可以形成肟2、苯二氮杂类N-氧化物3或异噁唑喹啉酮5。反应的产物取决于末端烯烃取代基R3的电子性质,以及取代基R1、R2和R4的空间填充能力。当烯烃中心电子贫乏(R3 = CO2Et)时,酮羰基化合物仅能转化为双环硝酮3,而醛对骨架结构的微小变化更加敏感,能够生成肟2、三环化合物5或两者的混合物。对于醛和酮底物,当烯烃中心带有芳基取代基(R3 = Ph)时,反应的主要产物是相应的肟,经过热激活后转化为三环异噁唑喹啉酮。