合成路线1

The intermediate naphthaleneboronic acid (XIX) has been obtained as follows: The bromination of the 3-methylanisole (X) with NBS gives the dibromo compound (XI), which is treated with sodium phenylsulfinate to afford the sulfone (XII). The condensation of (XII) with methyl crotonate (XIII) by means of LDA and KOH gives the butyric acid (XIV), which is cyclized to the tetralone (XV) by means of trifluoroacetic anhydride (TFAA). The aromatization of (XV) by means of t-BuOK or NaOH yields the 5-bromo-8-methoxy-3-methyl-1-naphthol (XVI), which is methylated with dimethyl sulfate to afford the bis(methyl) ether (XVII). The reaction of (XVII) with trimethyl borate and n-BuLi gives the boronic ester (XVIII), which is hydrolyzed with water and ammonium chloride yielding the desired naphthaleneboronic acid (XIX). Alternatively, the naphthaleneboronic acid (XIX) has been obtained as follows: The reaction of 2,4-dibromoanisole (XX) with n-BuLi and cyclohexyl(isopropyl)amine gives the benzyne intermediate (XXI), which, without isolation is cyclized with the lithium enolate of 3-methylcrotonic acid dimethylamide (XXII) to afford the previously described naphthol (XVI), which is purified by chromatography.