Chemistry of organo halogenic molecules. Part XCIV. The effect of fluorine on photochemical carbon-halogen bond cleavage in Z and E-1-fluoro-2-Halo-1,2-diphenylethylenes.
作者:A. Gregorčič、M. Zupan
DOI:10.1016/s0022-1139(00)81541-9
日期:1988.11
Introduction of fluorine on the olefinic carbon atom in the β-position to a carbon-halogen bond increased the photocleavage compared to the unsubstituted substrate, and reduced the electron transfer from the caged radical-pair to cationic intermediates. Increased solvent polarity resulted in enhanced photocleavage of the carbon-halogen bond.
在λ= 253.7nm处辐照Z和E-1-氟-2-卤代1,2-二苯基乙烯,得到Z和E-2-氟-1,2-二苯基乙烯和1,2-二苯基乙炔。光转化取决于分子的几何形状,存在的卤素原子和所用的溶剂。与未取代的底物相比,将氟在β位置的烯烃碳原子上引入碳-卤素键会增加光裂解,并减少电子从笼形自由基对向阳离子中间体的转移。溶剂极性的增加导致碳-卤素键的光裂解增强。