derivatives has been examined. The reaction affords furo[3,4-b]pyridine as transient intermediates; the latter undergo [4+2] cycloaddition with an electron-deficient dienophile. Acid/base-induced ring opening of the exo-cycloadducts followed by aromatization give substituted quinolines related to heterocyclic analogues of 1-arylnaphthalene lignans. An intramolecular variant of this protocol is also
已经研究了费歇尔卡宾配合物与2-炔基-3-
吡啶羰基衍
生物的偶联。反应得到
呋喃并[3,4- b ]
吡啶作为过渡中间体。后者与缺电子的亲双烯体进行[4 + 2]环加成反应。酸/所述的碱诱导的环开口外-cycloadducts随后芳构给予取代的
喹啉与1- arylnaphthalene木脂杂环类似物。该方案的分子内变体也可通过使用未活化的烯基系链来实现。然而,桥接的环加合物在经历自发开环以产生醇时是可溶的。该方法对于
呋喃[3,4- b]
喹啉中间体首次出现,可被双亲亲虫捕获。