Various 3-halogeno- and 3,5,5-trihalogeno-4-hydroxycyclopent-2-enone derivatives were prepared from 3,5,5-trichloro-4-hydroxycyclopent-2-enone (2), which is available in two steps from phenol via(1R*,4R*)-3,5,5-trichloro-1,4-dihydroxycyclopent-2-ene-1-carboxylic acid (1). Conjugate addition–elimination reactions of the 3-chloro-4-(dimethy-t-butylsilyloxy)-, the 3-chloro-4-tetrahydropyranyloxy-, and
由
3,5,5-三氯-4-羟基环戊-2-烯酮(2)制备各种3-卤代和3,5,5-三卤代-
4-羟基环戊-2-烯酮衍
生物(2),可分两步获得通过(1 R *,4 R *)-3,5,5-三
氯-1,4-二羟基环戊-2-烯-1-
羧酸(1)从
苯酚中得到。共轭3-
氯-4-(二甲基叔丁基甲
硅烷氧基)-,3-
氯-4-
四氢吡喃氧基-和5,5-二
氯-3-
碘-4-
四氢吡喃氧基-环戊-2-的加成-消除反应分别用
铜酸
锂和
镁酸
镁试剂制得的烯酮(20),(21)和(7)可高产率地产生合成上有用的3-烷基-
4-羟基环戊-2-烯酮。