5-dihydroxy-2-chloroglycidic ester or its rearrangement product, the acetonide protected 4,5-dihydroxy-3-chloro-2-oxo ester, with magnesium halides gave 4-halo-3-hydroxy-2-pyrone in excellent to reasonable yields in one pot. The mechanism of this novel one pot rearrangement–cyclization reaction is also proposed.
用卤化
镁处理
丙酮化物保护的4,5-二羟基-2-
氯缩水甘油酯或其重排产物,
丙酮化物保护的4,5-二羟基-3-
氯-2-氧代酯,得到4-卤代-3-羟基-2 -
吡喃酮一锅即可获得优异至合理的产量。还提出了这种新颖的一锅重排-环化反应的机理。