Réaction du diméthylcuprate de lithium avec les dérivés carbonylés α,β-insaturés α-fluorés et α-chlorés
作者:C. Chuit、R. Sauvêitre、D. Masure、J.F. Normant
DOI:10.1016/0040-4020(79)87045-3
日期:——
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。