Divergent change of regioselectivity in nucleophilic addition of electron deficient allylic tin reagents to 4-acylpyridinium salts; selective formation of 4,4-disubstituted 1,4-dihydropyridines
作者:Ryohei Yamaguchi、Katsunobu Mochizuki、Sinpei Kozima、Hidemasa Takaya
DOI:10.1039/c39930000981
日期:——
Nucleophilic additions of 2-methoxycarbonyl- and 2-cyano-allyltributyltins to 4-methoxycarbonyl-, 4-formyl-, and 4-acetyl-pyridines activated by methyl chloroformate afford 1,4-adducts exclusively or predominantly, while the reactions of 2-methylallyltributyltin with 4-methoxycarbonyl-and 4-acetyl-pyridines activated by methyl chloroformate give the 1,2-adducts exclusively.
2-甲氧基羧酸基和2-氰基-烯丙基三丁基锡与由氯甲酸甲酯活化的4-甲氧基羧酸基、4-甲醛和4-乙酰基吡啶发生亲核加成反应,主要或专门生成1,4-加成产物,而2-甲基烯丙基三丁基锡与由氯甲酸甲酯活化的4-甲氧基羧酸基和4-乙酰基吡啶的反应则专门生成1,2-加成产物。