Stereochimie et mecanisme de l'ouverture par les amines d'ions N-alcoxypyridinium
作者:H. Sliwa、A. Tartar
DOI:10.1016/0040-4020(79)80072-1
日期:1979.1
with irreversible cyclization of an ylide to the bicyclic intermediate 3 which suffers subsequent ring opening to 3-ω-aminobutadienylisoxazol-4 ones in methanol. The different courses of the reaction is tentantively explained by means of HSAB theory. Stereochemistry of the primary open products is consistent with a disrotatory ring opening of cis-dihydropyridine adducts resulting from amine addition to
所述Ñ -alkoxypyridinium盐1,与吡咯烷,哌啶和二乙胺,经历在乙腈可逆开环。这与叶立德不可逆地环化成双环中间体3竞争,该双环中间体3随后在甲醇中开环成3-ω-氨基丁二烯基异恶唑-4。借助于HSAB理论来解释性地解释反应的不同过程。初级开放产物的立体化学与由胺加成盐1或双环离子3所形成的顺式-二氢吡啶加合物的旋转开环一致。这些主要产物经过进一步异构化和全反式对于异恶唑啉衍生物,已经分离出结构。一个的转换Ñ -alkoxypyridinium盐取代butadienylisoxazolones例示了新型杂环变换可以由PARC-ANRO序列描述:质子抽象,亲核试剂的关环加成,和开环。