摘要
二氟二碘甲烷(CF2I2,1)与乙烯基乙醚和Na2S2O4在DMSO和乙醇的混合溶剂中反应得3,3-二氟-3-碘丙醛的乙缩醛[ICF2CH2CH(OEt)2](3).3在锌粉的作用下发生偶联反应生成二缩醛[(EtO)2CHCH2CF3CF2CH2CH(OEt)2]( 5)缩醛3或5与烯醇硅醚在SnCL4作用下发生交叉偶联反应.3在锌粉或保险粉的引发下与烯醇硅醚发生加成反应3和5分别转化成硫缩醛ICF2CH2CH(SR)2(13),(RS)2CHCH2CF2CF2CH2CH(SR)2(14)或O,S-缩醛13消除HI得1,1-二氟乙烯衍生物.
Difluorodiiodomethane ( CF2I2, 1) can react with vinyl ethyl ether by Na2S2O4 in a solvent [V (EtOH) : V ( DMSO) = 10 : 1] at room temperature for 8 hours 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 - coupling reactions of the acetals 3 and 5 with trimethylsilyl enol ethers produce ketones ICF2CH2CH (OEt) CH2COR (8) and (RCOCHCH)-H-2 (OEt) CH2CF2CF2CH2CH (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 ICF2CH2CH(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 used. The elimination of HI from 13 by NEt3 results in the formation of 1,1 - difluoroethylene derivatives.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2001年第10期1722-1729,共8页
Acta Chimica Sinica
