Organic Reactions, Volume 2

DISPLACEMENT OF SUBSTITUENTS 11
Allyl aryl ethers with halogen atoms in the allyl group rearrange very
poorly; /3-bromoallyl phenyl ether is reported to give 3d% rearrangement
after ninety minutes at 215°, 50% being recovered unchanged. 48 ^
Later experiments have not confirmed this, phenolic resins being the only
product observed; however, by rearrangement of the corresponding
chloro compound, a 24% yield was obtained. 43 The 7-halogen ethers,
such as C6H6OCH2CH=CHC1, do not rearrange, although they do
decompose and yield some phenol. 43
Effect of Substituents in the Aromatic Nucleus. Substituents in the
aromatic nucleus do not affect the ease of rearrangement greatly, and ft
is noteworthy that meta directing groups in the nucleus do not hinder
the jreaction, nor do the strongly ortho-para directing groups seem to
favor it greatly. Rearrangements have been reported for allyl aryl
ethers with the following substituents in the aromatic nucleus (Table II):
hydroxyl, methoxyl, methylenedioxy, allyloxy (rearrangement involving
migration of two allyl groups), formyl, carboxyl, acetyl, propionyl,
7-hydroxypropyl, carbethoxyl, /3-carbomethoxyvinyl, halo, nitro, amino,
acetamino, and azo. Allyl ethers derived from the following aromatic
and heterocyclic nuclei have been rearranged: benzene, toluene, xylene,
allylbenzene, naphthalene, anthracene, phenanthrene, fluorene, biphenyl,
hydrindene, fluorescein, quinaldine, flavone, chromone, dibenzofuran,
coumarin, and benzothiazole.
Displacement of Substituents. No complications are caused by the
presence of ester groups in the aromatic nucleus, but, if a free carboxyl or
aldehyde group is present in the position ortho or para to the ether linkage,
it may be displaced by the allyl group "(Table II, Section C). 0-
Allyl-3,5,-diaIlylsalicylic acid (XXXII) gives a quantitative yield of
2,4,6-triallylphenok (XXXIII), the evolution of carbon dioxide starting
at 100 0 . 4 * O-AUylsalicylic acid (XXXIV) when heated at 175-180°
gives 23% of 2-allylphenol, with loss of carbon dioxide, and 64% of
3-allylsalicylic acid (XXXV), 46 A carboxyl group in the para position
also is eliminated easily; thus 3,5-diallyl-4-allyloxybenzoic acid (XXXVI)
OC3H6 OH OC3H6 OH
C3H6
XXXIII XXXIV XXXV
42 v. Braun, Kuhn, and Weismantel, Ann., 449, 264 (1926).
*' Hurd and Webb, J. Am. Chem. Soc., 58, 2190 (1936).
44 Claisen and Eideb, Ann., 401, 79 (1913).
46 Tarbell and Wilson, J. Am. Chem. Soc., 64, 607 (1942).