Depending on the nature of the halogen, α-fluoro- and α-chloro-α,β-unsaturated carbonyl compounds (whose reduction potentials are greater than − 2.4V) react in different ways with lithium dimethylcuprate. With α-fluoro derivatives, both 1,2- and 1,4-addition is observed, their ratios depend on the steric hindrance of the β-position. 1,4-Addition products are obtained from aldehydes and β-monosubstituted
根据卤素的性质,α-
氟代和α-
氯代-α,β-不饱和羰基化合物(其还原电势大于-2.4V)以不同的方式与二
甲基铜乙酸锂反应。对于α-
氟衍
生物,可以同时观察到1,2-和1,4-加成,它们的比例取决于β-位的空间位阻。从醛和β-单取代的α-
氯代-α,β-
烯键式
酮和
酯获得1,4-加成产物。β,β-二取代的α-
氯代
酮和
酯只能通过卤素
金属交换来还原卤素。