A useful magnesium reagent for the preparation of 1,1-difluoro-2-hydroxyphosphonates from diethyl bromodifluoromethylphosphonate via a metal—halogen exchange reaction
作者:Rachel Waschbüsch、Mohammad Samadi、Philippe Savignac
DOI:10.1016/s0022-328x(96)06541-2
日期:1997.2
When (EtO)2P(O)CF2Br (1) is treated with isopropylmagnesium chloride in THF at low temperature it gives a magnesium species (2) which undergoes reactions with strong electrophiles (HCl, TMSCl, halogens, aldehydes and ketones). The formation of products depends strongly on the reaction conditions. With 1.5 equivalents of 2 between −78 and 0°C, a conversion of more than 90% of aldehydes and ketones into
将(EtO)2 P(O)CF 2 Br(1)在THF中用异丙基氯化镁在低温下处理时,得到镁物质(2),该镁物质与强亲电试剂(HCl,TMCCl,卤素,醛和酮)发生反应。产物的形成在很大程度上取决于反应条件。在-78至0°C之间使用1.5当量的2,可以实现90%以上的醛和酮转化为2-羟基膦酸酯(7和8)。这些化合物(7和8)在碱(NaH,LDA)存在下重排成2,2-二氟乙基磷酸酯,而不会同时形成1,1-二氟烯烃。