The reaction of trifluoroacetaldehyde N,O-acetals with more than 2 equiv of alkyllithiums at −78 °C resulted in regiospecific defluorinative alkylation with unusual regioselectivity to give α,α-difluoroketone N,O-acetals in excellent yield. In contrast, under similar conditions, trichloroacetaldehyde N,O-acetals gave simple mono-dechlorinated product without the alkyl transfer reaction from alkyllithiums
三
氟乙醛N,O-
缩醛在-78°C下与2个以上当量的烷基
锂反应导致区域特异性的脱氟烷基化,具有异常的区域选择性,从而以优异的收率得到α,α-二
氟酮N,O-
缩醛。相反,在相似的条件下,
三氯乙醛N,O-
乙缩醛产生简单的单脱
氯产物,而没有从烷基
锂到生成的中间体的烷基转移反应。