base gives 4-chloroazodienes, which were found to combine with a variety of electron rich olefins to yield chloro-substituted tetrahydropyridazines. These chloroazodiene cyclizations are best characterized as inverse electron demand, 4+2 hetero Diels-Alder reactions that maintain a high degree of regio- and stereochemical control. The chloro-substituted tetrahydropyridazines that are formed give high yields
二
氯hydr酮与Hünig碱的反应生成了4-
氯偶氮二烯,发现它与多种电子富集的烯烃结合,生成
氯取代的四氢
哒嗪。这些
氯偶氮二烯环化的最佳特征是反电子需求,4 + 2杂Diels-Alder反应,可维持高度的区域和立体
化学控制。形成的
氯取代的四氢
哒嗪在用碱处理后可得到高产率的取代的
哒嗪。
氯偶氮二烯环化成四氢
哒嗪并随后进行芳构化的顺序构成了取代的
哒嗪的新的通用合成方法。