合成路线1

2. In an alternative synthesis, 5-bromosalicylaldehyde (XIII) was alkylated with bromoacetaldehyde dimethyl acetal (XIV) to afford ether (XV). Further Baeyer-Villiger reaction with (XV) produced phenol (XVI), which was cyclized to the benzodioxine (XVII) with p-TsOH. Lithiation of (XVII), followed by reaction with triisopropyl borate and hydrolytic work-up, gave boronic acid (XVIII). Aldehyde (II) was treated with MCPBA yielding phenol (XIII), which was iodinated in the presence of tert-butylamine to give the bromo iodo derivative (XIV). Sequential Suzuki coupling of bromo iodo compound (XIV) with boronic acid (XVIII) yielding (XIX), and then with boronic acid (I) provided terphenyl (XX). Hydrolysis of the methyl acetal of (XX) using p-TsOH gave cyclic hemiacetal (XXI). Finally, Wittig reaction of (XXI) with the phosphorane prepared from isopropyl triphenylphosphonium iodide and n-BuLi provided the title compound.