Titanium Tetrachloride Induced Fries Rearrangement: A New Route to Disubstituted 2′- Hydroxypropiophenones

Abstract

Fries rearrangement of some dialkylphenyl propionates with titanium tetrachloride proves to be a convenient route to hindered dialkyl 2′-hydroxypropiophenones. The sequential use of soft titanium tetrachloride to perform the Fries rearrangement followed by hard aluminum chloride to achieve the elimination of a protecting tert-butyl group allows the synthesis of some previously unknown 3′,6′- and 5′,6′-dialkyl-2-hydroxypropiophenones.