合成路线1

In a different synthetic strategy, the required dibromostyrene (XIV) was prepared in low yield by Wittig-like condensation of 3-hydroxy-4-methoxybenzaldehyde (XII) with carbon tetrabromide in the presence of PPh-3. In an improved process, the phenolic hydroxyl of (XII) was first protected as the silyl ether (X), which was then condensed with CBr4/PPh3 to give (XIII). Subsequent desilylation of (XIII) with tetrabutylammonium fluoride provided (XIV). Stereoselective debromination of the dibromostyrene (XIV) with tributyltin hydride and tetrakis(triphenylphosphine)palladium(0) led to the Z-bromostyrene (XV). This was finally subjected to a palladium-catalyzed Suzuki coupling with 3,4,5-trimethoxybenzeneboronic acid (XVI) to furnish the title Z-olefin as the major isomer