合成路线1

The Friedel Crafts condensation of 2,5-dichloro-2,2,5,5-tetramethylhexane (I) with toluene (II) by means of AlCl3 gives 1,1,4,4-tetramethyl-1,2,3,4-tetrahydronaphthalene (III), which is submitted to a new condensation with the pyridine-2-carbonyl chloride (IV) by means of AlCl3 in dichloromethane to yield the diaryl ketone (V). The reaction of (V) with methyltriphenylphosphonium bromide (VI) and NaNH2 affords the 1,1-diarylethylene (VII), which is treated with Et2Zn and Cl-CH2-I in dichloromethane to provide the 1,1-diarylcyclopropane (VIII). Finally, the ester group of (VIII) is hydrolyzed with KOH in methanol/water to yield the target carboxylic acid.