Addition of Trifluoromethyltrimethylsilane to Acyl Phosphonates: Synthesis of TMS-Protected 1-Alkyl-1-trifluoromethyl-1-hydroxyphosphonates and 1-Aryldifluoroethenyl Phosphates
摘要:
Addition reactions of nucleophilic CF3TMS to acyl phosphonates were investigated. Various acyl phosphonates reacted readily with CF3TMS in the presence of K2CO3 in DMF at rt to give 1-alkyl-2,2,2-trifluoro-1-trimethylsilyloxyethylphosphonate in 70-90% yields. When benzoyl phosphonates were used as starting material, after addition of CF3, the formed alcoholate undergoes phosphonate-phosphate rearrangement to form the acyl anion, followed by elimination of F- to give 1-aryldifluoroethenyl phosphates in 87-97% yields. As a representative example, vinylphosphate 6a was converted into 2,2-difluoro-1-phenylethanone 7 with 6 N HC1/EtOH/reflux or CAN/NaOH/MeOH/O degrees C in 82-90% yields.
Organocuprate-induced substitution of the enol oxygen moiety in 2,2-difluoro enol phosphates with allyl halides: a novel route to -diffluoroolefins from chlorodifluoromethyl ketones
作者:Takashi Ishihara、Masayuki Yamana、Teiichi Ando
DOI:10.1016/s0040-4039(00)94166-2
日期:1983.1
2,2-Difluoro-1-arylethenyl diphenyl phosphates, prepared from chloro-difluoromethyl ketones and diphenyl phosphite, reacted with dibutylcopperlithium and successively with various allyl halides to give allylated gem-difluoroolefins in moderate to excellent yields.
Selective preparation of 1-substituted 2,2-difluoroethenyl phosphates or 1-hydroxyalkanephosphonates through the reaction of chlorodifluoromethyl ketones with dialkyl or diaryl phosphites
Various chlorodifluoromethyl ketones react readily with dialkyl or diaryl phosphites in the presence of triethylamine at the reflux temperature of tetrahydrofuran to give the corresponding dialkyl or diaryl 1-substituted-2,2-difluoroethenyl phosphates in good yields, whereas the similar reaction conducted at lower temperature (0-20 °C) affords 1-(chlorodifluoromethyl)-1-hydroxyalkanephosphonates almost