Synthesis of γ-(Electron-withdrawing group)-Substituted α,α-Difiuoro Ketones by UV-Initiated Addition of lododifiuoromethyl Ketones with Electron-Deficient Alkenes

摘要

Under UV irradiation (254 nm), lododifiuoromethyl phenyl, alkyl, and chlorodifluoromethyl ketones [RC(O)CF_2I (1), R: Ph (a); n-C_4H_9 (b), n-C_6H_(13) (c), C1CF2 (d)] were reacted with a series of alkyl acrylates (CH_2=CHCO_2R', R': Et, n-Bu, t-Bu, and Me), N,N-dimethylacrylamide, acrylonitrile, and vinyl methyl ketone in the absence of solvent at ambient temperature. High yields of the corresponding 1:1 addition products [RC(O)CF_2CH_2CKICQ_2Et (2)] weie obtained when 1 reacted with ethyl acrylates(50-79%). The reaction of la with n-butyl acrylate gave a similar 1:1 adduct (51%). However, an addition-reduction product, PhC(O)CF_2CH_3CH_2CO_2H, was isolated in 44% yield when terc-butyl acrylate was reacted with la. More interestingly, both 1:1 and