合成路线1

Iodination of 3-methylcyclohexenone (I) using iodine and azidotrimethylsilane produced the iodo ketone (II) (1). Palladium-catalyzed coupling of iodide (II) with 2-(tributylstannyl)ethenyltrimethylsilane (III), prepared from (trimethylsilyl)acetylene and tributyltin hydride, furnished the silylethenyl cyclohexenone (IV), which was further treated with iodine to yield vinyl iodide (V) (1,2). Ethyl 4-ethynylbenzoate (VIII) was prepared by reaction of ethyl 4-iodobenzoate (VI) with (trimethylsilyl)acetylene (VII) in the presence of palladium catalyst (1). Heck reaction between acetylene (VIII) and vinyl iodide (V) provided adduct (IX). Conjugate addition of the in situ generated lithium dimethylcuprate to the unsaturated ketone (IX) gave the 3,3-dimethyl cyclohexanone (X). Treatment of (X) with triflic anhydride and a hindered base produced the desired vinyl triflate (XI) along with its vinyl regioisomer, which were separated by preparative chromatography. Reaction of triflate (XI) with 4-tolylzinc bromide (XIII), prepared from 4-iodotoluene (XII), yielded the phenylcyclohexene derivative (XIV). The ethyl ester group of (XIV) was finally hydrolyzed to the corresponding carboxylic acid using NaOH.