合成路线1

The intermediate trans-8-oxo-5-(3,4,5-trimethoxyphenyl)-5,6,7,8-tetra-hydronaphtho[2,3-d][1,3]benzodioxole-6-carboxylic acid ethyl ester (XI) has been obtained by several different ways: (a) The condensation of benzophenone (XXXVIII) with diethyl malonate (XXXIX) by means of t-BuOK gives the alkylidenemalonate (XL), which is hydrogenated with H2 over Pd/C to the alkylmalonate hemiester (XLI). The reaction of (XLI) with acetyl chloride affords the mixed anhydride (XLII), which is finally cyclized to the target (XI) by means of SnCl4. (b) The cyclization of the malonic ester derivative (XLIII) by means of Ti(CF3--CO2)3 gives the 5-(3,4,5-trimethoxyphenyl)-5,6,7,8-tetrahydronaphtho [2,3-d][1,3]dioxole-6,6-dicarboxylic acid dimethyl ester (XLIV), which is finally oxidized and decarboxylated with NBS and NaOH in methanol to afford the target intermediate (XI). (c) The cyclization of the benzylidenemalonate (XLV) with the aryllithium derivative (XLVI) gives the 8-methoxy-5-(3,4,5-trimethoxyphenyl)-5,6,7,8-tetrahydronaphtho[2,3-d][1,3]dioxole-6,6-dicarboxylic acid dimethyl ester (XLVII), which is demethylated with TFA and oxidized with CrO3 and pyridine to the target compound (XI). (d) The cyclopropanation of the chalcone (XLVIII) with (ethoxycarbonyl) (dimethylsulfonium)methylide (XLIX) gives the cyclopropanecarboxylate (L), which is finally rearranged with BF3/Et2O to the target intermediate (IX).