A G. C./M. S. study of the reaction and decomposition products of pentafluorophenyl-grignard and lithium reagents

摘要

Decomposition and side reactions of, and the syntheticuse of, pentafluorophenylmagnesium bromide and pentafluorophenyllithiumhave been investigated using G,C9/M.S,techniques• Their reactions with reagents such as CgF^X(X - H, F, CI, Br, 1), C6F4X2 (X - H, CI)f C6F3C13, C6H6.(CgX5)3P (X = H, F), (C6X5)3P=0 (X = H, F), (CgX5)Si (CH3)3(X = H, F) and (CH0K SiCl , n = 1,2, in ether orether/n-hexane were studied•In addition to the principal reaction of syntheticuse, namely the replacement of a halogen by a pentafluorophenylgroup, two types of side reactions were observed*These were (i) intermolecular loss of LiF via a nucleophilicsubstitution, and (ii) intramolecular loss of LiF, followedby the addition of either inorganic salts such as lithiumor magnesium halides, or organometal compounds such asorganolithium or organo-Grigaard*G.C«/M.S. techniques were routinely employed to studycomplicated reaction mixtures. Although mass spectrometryalone has disadvantages for the identification of isomers,deduction of the most probable pathway often helps overcomethis problem.