Intramolecular carbenoid ylide forming reactions of 2-diazo-3-keto-4-phthalimidocarboxylic esters derived from methionine and cysteine
作者:Marc Enßle、Stefan Buck、Roland Werz、Gerhard Maas
DOI:10.3762/bjoc.8.49
日期:——
three steps. Upon rhodium-catalysed dediazoniation, two intramolecular carbenoid reactions competed, namely the formation of a cyclic sulfonium ylide and that of a six-ring carbonyl ylide. The S-methyl and S-benzyl ylides 12a and b could be isolated, while S-allyl ylide 12c underwent a [2,3]-sigmatropic rearrangement. The short-lived carbonyl ylides derived from methionine and S-benzylcysteine formed head-to-tail
蛋氨酸、S-苄基半胱氨酸和S-烯丙基半胱氨酸分三步转化为2-重氮-3-氧代-4-邻苯二甲酰亚胺甲酸酯8a-c。在铑催化的脱重氮反应中,两个分子内类胡萝卜素反应竞争,即形成环状锍叶立德和六环羰基叶立德。可以分离S-甲基和S-苄基叶立德12a和b,而S-烯丙基叶立德12c经历[2,3]-σ重排。由甲硫氨酸和 S-苄基半胱氨酸衍生的短寿命羰基叶立德通过 [3 + 3]-环加成形成头尾二聚体,并且可以被外部亲偶极试剂捕获,而 S-烯丙基衍生物 14c 通过以下方式产生五环化合物 17分子内[3 + 2]-环加成反应。