2-aza-1,3-dienes with electron-releasing substituents at the 1,3 positions. Reagents for the construction of pyridine and pyrimidine derivatives
作者:Georges Morel、Evelyne Marchand、Jean-Paul Pradère、Loic Toupet、Sourisak Sinbandhit
DOI:10.1016/0040-4020(96)00546-7
日期:1996.7
with a variety of electron-deficient dienophiles to yield pyridine or pyrimidine derivatives. The stereochemistry of the hetero Diels-Alder reaction in the cases of dimethyl fumarate and acrylonitrile has been assigned by X-ray diffraction analyses of the resulting tetrahydropyridines and corresponds to an exo selectivity. The number and nature of cycloadducts in the cases of dimethyl acetylenedicarboxylate
通过N-亚硫基乙am碘化物的去质子化,由N-硫代酰基乙acet制备带有1和3-供体取代基的新的2-氮杂-1,3-二烯。2-氮杂-3-(二甲基氨基)-1-(甲硫基)-1-苯基丁二烯(3)被残留的前体盐作为异二烯基团原位捕获,得到嘧啶5。取代的2-氮杂-1-(二甲基氨基)-3-(甲硫基)类似物容易与各种缺电子的亲二烯体反应,生成吡啶或嘧啶衍生物。富马酸二甲酯和丙烯腈情况下的杂Diels-Alder反应的立体化学已通过所得四氢吡啶的X射线衍射分析确定,并对应于exo选择性。在乙炔二羧酸二甲酯和异硫氰酸苯酯的情况下,环加合物的数量和性质取决于C-4取代。由C-4未取代的氮杂丁二烯8获得的结果由涉及伯[4 + 2]加合物中二甲基氨基的1,3-迁移的烯丙基重排解释。