General Reactivity of 2-Lithiobenzothiazole to Various Electrophiles and the Use as a Formyl Anion Equivalent in the Synthesis of α-Hydroxy Carbonyl Compounds
作者:Hidenori Chikashita、Megumi Ishibaba、Keiji Ori、Kazuyoshi Itoh
DOI:10.1246/bcsj.61.3637
日期:1988.10
demonstrated by its reaction with phenacyl halides and 5-chloro-2-pentanone leading to the formation of benzothiazolyl-substituted small-ring ethers. In order to demonstrate the value of 2-lithiobenzothiazole as a masked formyl anion, 2-(α-hydroxyalkyl)benzothiazoles were transformed into α-hydroxy carbonyl compounds in three reaction steps without masking the α-hydroxy groups. Quaternization of various
2-锂硫代苯并噻唑与各种亲电子试剂如醛、酮、羧酸酯、内酯、腈和酰胺的反应提供了预期的加成和取代产物。三甲基甲硅烷基氯很容易与苯并噻唑阴离子反应生成 2-三甲基甲硅烷基苯并噻唑,而常见的烷基卤化物,包括伯碘化物和苄基卤化物,以及环氧化物,不与阴离子反应。阴离子的这种特征亲核性也通过它与苯甲酰卤和 5-氯-2-戊酮的反应导致苯并噻唑基取代的小环醚的形成得到证实。为了证明 2-硫代苯并噻唑作为掩蔽甲酰基阴离子的价值,2-(α-羟基烷基)苯并噻唑在三个反应步骤中转化为α-羟基羰基化合物,而不会掩盖α-羟基。各种 2-(α-羟烷基)苯并噻唑与甲基碘在 DMF 中季铵化得到相应的 2-(α-羟烷基)-3-甲基苯...