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.
                                    某些二烷基
苯丙酸酯与
四氯化钛的Fries重排证明是一条合成受阻的二烷基2′-羟基丙酰苯酮的便捷途径。先使用较温和的
四氯化钛进行Fries重排,然后再用较强的
氯化铝去除保护性叔丁基基团,这样可以合成一些以前未知的3′,6′-和5′,6′-二烷基-2-羟基丙酰苯酮。