The reaction and its product conversion of difluorodiiodomethane with ethyl vinyl ether

Difluorodiiodomethane ( CF2I2, 1) can react with vinyl ethyl ether by Na2S2 O4 in a solvent [V (EtOH) : V ( DMSO) = 10 : 1] at room temperature for 8 h ours to give diethyl 3, 3 - difluoro - 3 - iodopropylacetal [ICF2CH2CH (OEt )(2)] (3) in 60% yield. The coupling of 3 with zinc in DMF affords [(EtO)(2 )CHCH2CF2CF2CH2CH(OEt)(2)] (5) in 60% yield. The SnCl4 - promoted cross - c oupling reactions of the acetals 3 and 5 with trimethylsilyl enol ethers pr oduce ketones ICF2CH2CH (OEt) CH2COR (8) and (RCOCHCH)-H-2 (OEt) CH2CF2CF2C H2CH (OEt) CH2COR (9) respectively. 3 can add to trimethylsilyl enol ethers initiated by Zn or sodium dithionite to yield (EtO)(2)CHCH2CF2CH2CH (OTMS) C6H5 ( 10c) or (EtO)(2)CHCH2CF2CH2COC (CH3)(3) (11a). The acetals 3 and 5 can be converted by BF3 . Et2O into the corresponding dithioacetals ICF2CH2 CH(SR)(2)(13), (RS)(2)CHCH2CF2CF2CH2CH(SR)(2)(14) or O, S - acetal EtOCH(SR ) CH2CF2CF2CH2CH (SR) (OEt) (15) depending upon the concentration of RSH us ed. The elimination of HI from 13 by NEt3 results in the formation of 1,1 - difluoroethylene derivatives.