1,3-Dipolar character of six-membered aromatic rings. Part 51. Cycloadditions of 1-(β-benzoylvinyl)-3-oxidopyridiniums and subsequent transformations
作者:Alan R. Katritzky、Soheila Rahimi-Rastgoo、Gebran J. Sabongi、Gerhard W. Fischer
DOI:10.1039/p19800000362
日期:——
β-p-Chloro-, β-p-bromo-, and β-2-chloro-5-nitrobenzoyl-vinyl chloride react with 3-hydroxypyridine to give quaternary salts which with base give the corresponding betaines. These betaines undergo thermal dimerisation and cycloadditions with mono- and di-enes at the 2,6- and 2,4-positions, respectively. The site-, regio-, and stereo-selectivity of these cycloadditions are discussed with reference to
β-对氯,β-对溴和β-2-氯-5-硝基苯甲酰-氯乙烯与3-羟基吡啶反应生成季盐,与碱生成相应的甜菜碱。这些甜菜碱分别在2,6-位和2,4-位进行单烯烃和二烯烃的热二聚和环加成反应。这些环加成的位点,区域和立体选择性参考MO预测进行了讨论。加合物中的β-芳基乙烯基取代基可以被水解除去。