Aluminium chloride, oxidative rearrangement

Initially Robinson and Sugasawa (8) proposed that laudanosoline (5), prepared from laudanosine (4) by O-demethylation with aluminium chloride in refluxing xylene, could be oxidized to an aporphine or morphine prototype. To demonstrate that no rearrangement had occurred, 4 was regenerated from 5 by O-methylation. Oxidation of 5 was accomplished with chloranil in buffered alcohol solution, and 6 was isolated in 60% yield as the chloride (Scheme 1). Di-benzopyrrocoline 6 was also obtained in 30-50% yield when aqueous solutions... 

Reaction of the hydrocarbons in this series with phenols or phenol ethers in the presence of suitable catalysts is well known, a-fenchene and phenol yielding a mixture of o- and p-isofenchylphenols in the presence of aluminium phen-oxide practically the same reaction was described seven years ago. Reaction of camphene with a phenol ester in the presence of stannic chloride is reported to give a bornyl compound, but terpenoid rearrangements are notorious under such conditions, and it is doubtful whether this is the only product. 3,3-Dibromocamphor (261) has been converted into substituted cyclo-hexanecarboxylic acids by the route shown in Scheme 13. ... 

Preparation by Fries rearrangement of hydroquinone dibenzoate with aluminium chloride [249,250], (good OH yield) [251], at 140° for 1 h (33%) [252], at 190-200° for 1 h 30 min (50%) [253] or at 200° for 20 min [20]. Preparation by oxidation of 5-(benzoyloxy)-2,3-diphenyl-benzofuran with chromium trioxide in boiling acetic acid for 2 h, followed by saponification of the keto ester formed with boiling 8% sodium hydroxide in ethanol [254]. 

Preparation by Fries rearrangement of 4-acetoxydiphenyl oxide in the presence of aluminium chloride at 120° (90%) [1852],... 

The bromination and oxidation of securinine have been reported (Scheme 87). Oxidative difunctionalization of 2-amino-4//-pyrans occurs with iodobenzene diacetate and A -chlorosuccinimide reagents. An oxidative rearrangement of [7]helicene by heating with iron(n) chloride and aluminium(III) chloride involves skeletal rearrangement with the loss of helicity (Scheme 88). ... 

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