The adducts 10, formed in high yield by condensations between the benzotriazole dianion 2 and enals 9, undergo smooth oxidation by manganese(IV) oxide to provide the expected conjugated enones. These then cyclise at varying rates, depending upon the substitution pattern around the enone function, by intramolecular Michael addition of the NHBoc group to provide examples 13 of a novel ring system based upon a 4,5,6,7-tetrahydro-1,2-benzodiazepine core. Allylic acetates 16 derived from the initial adducts 10 also undergo cyclisations via the derived π-allyl palladium complexes 15 to provide examples of the corresponding 4,5-dihydro-1,2-benzodiazepinenes 17, but in a less general manner.
苯并三唑偶联物 2 和
烯醛 9 缩合形成的加合物 10 收率很高,在
氧化锰(IV)的作用下顺利
氧化,生成预期的共轭
烯酮。然后,根据
烯酮官能团周围的取代模式,通过 NHBoc 基团的分子内迈克尔加成,这些
烯酮会以不同的速率发生环化,从而形成基于 4,5,6,7-四
氢-1,2-
苯并二氮杂卓核心的新型环状体系的实例 13。由初始加合物 10 衍生出的
烯丙基乙酸酯 16 也会通过衍生出的π-
烯丙基
钯络合物 15 发生环化反应,以提供相应的 4,5-二
氢-1,2-
苯并二氮杂卓 17 的实例,但采用的方式不太通用。