Intramolecular N-acyliminium ion versus Friedel–Crafts cyclization onto 3-indoles: synthesis of the novel rings pyrrolizino[2,1-b]indole and homologues
作者:Raffaella Cincinelli、Sabrina Dallavalle、Lucio Merlini、Raffaella Nannei、Leonardo Scaglioni
DOI:10.1016/j.tet.2009.02.036
日期:2009.4
γ-oxoamides causes Friedel–Crafts intramolecular cyclization to β-carbolinones and dihydro-2H-azepino[3,4-b]indol-1-ones, in contrast to secondary δ-,ɛ-, and ζ-oxoamides, which cyclize to the novel heterocyclic rings pyrrolizino[2,1-b]indole, indolizino[2,1-b]indole, and 9a,11-diaza-indeno[1,2-a]azulene, via an intermediate N-acyliminium ion. Tertiary amides lead only the Friedel–Crafts ring closure, thus
吲哚-2-羧酸β-和γ-氧代酰胺的酸处理导致Friedel-Crafts分子内环化为β-咔啉酮和二氢-2 H-氮杂环庚烷[3,4- b ]吲哚-1-酮,与仲δ相反-,ɛ-和ζ-氧代酰胺,可环化成新型杂环吡咯并[2,1- b ]吲哚,吲哚并[2,1- b ]吲哚和9a,11-二氮杂茚并[1,2-通过中间的N-酰基亚胺离子形成α ] azulene。叔酰胺仅导致Friedel-Crafts环闭合,从而允许合成更大的稠合环。