Nucleophilic vinylic substitution with transition metal carbonyl anions—a rare case of a halophilic reaction mechanism
作者:P.K Sazonov、G.A Artamkina、V.N Khrustalev、M.Yu Antipin、I.P Beletskaya
DOI:10.1016/s0022-328x(03)00531-x
日期:2003.9
intermediate carbanion [RfCFCF]− on the carbonyl ligand of Re(CO)5Hal. The involvement of [RfCFCF]− is demonstrated by their trapping with t-BuOH or CH-acid, which gives the protodehalogenated alkenes I-H and II-H, and suppresses the nucleophilic substitution reaction leading to I-Fe, II-Fe or V-Cl. Arguments against a radical/SET mechanism for the substitution reaction are also advanced.
多氟化链烯基卤化物的反应ž - (CF 3)3 CCFCFHal(HAL =氯,我-氯,哈尔= Br的,我-溴)和CF 2 CFBr(II -溴)与[CpFe的量(CO)2 ] K(FpK)和[Re(CO)5 ] Na通过羰基金属阴离子对卤素的初始攻击而继续进行。与FPK反应得到少量σ -烯基配合物的ž -R ˚F CFCFFe(CO)2的Cp(我-铁,II -铁)(3–30%),但主要导致二聚体[CpFe(CO)2 ] 2。与反应[的Re(CO)5 ]的Na产生阴离子卤(酰基)铼酸盐顺- [ Ž -R ˚F CFCF(CO)的Re(CO)4哈尔]的Na(V -氯,V -溴,VI)( 70-90%)被分离出来,卤代(酰基)雷尼酸酯VI(Rf = F)通过X射线结构分析来表征。卤代(酰基)铼酸盐从中间碳负离子的攻击导致[R ˚F CFCF] -上的Re(CO)的羰基配位体5哈尔 的[R参与˚F