100600-02-0Relevant academic research and scientific papers
Aromatic Rearrangements in the Benzene Series. Part 4. Intramolecularity of both the ortho- and para-Rearrangements of Benzyl Phenyl Ether as shown by Labelling Experiments
Hart, Lionel S.,Waddington, Catherine R.
, p. 1607 - 1612 (2007/10/02)
The rearrangement of a mixture of Ph13CH2OPh and PhCH218OPh (with some unlabelled ether) catalysed by AlBr3 in homogeneous solution in 1,2,4-trichlorobenzene and in nitrobenzene has been examined.The literature report of this reaction was shown to be substantially correct: the reaction is very rapid, and ortho-migration of the benzyl group predominates, but does not (in contrast to the earlier report) occur exclusively.The ortho : para ratio of the rearrangement products is ca. 11 in 1,2,4-trichlorobenzene and ca. 4.7 in nitrobenzene.The ether undergoes rearrangement in both solvents without prior scrambling of isotopic labels.In trichlorobenzene, the reaction appears to be almost completely intramolecular, even for para-rearrangement: o-benzylphenol is unscrambled, the para-isomer almost so.In nitrobenzene, o-benzylphenol is virtually unscrambled, the para-isomer ca. 25percent so.A mechanism involving a tight ion-pair (from which some leakage occurs in nitrobenzene) is proposed, and possible explanations of the high ortho : para ratios are considered.
