Br[C:2]1[CH:7]=[C:6]([O:8][CH3:9])[C:5]([O:10][CH3:11])=[CH:4][C:3]=1[CH:12]1[O:16][CH2:15][CH2:14][O:13]1.O1CCCC1.C([Li])CCC.[CH:27]1[C:32]([CH:33]=[O:34])=[CH:31][C:30]2[O:35][CH2:36][O:37][C:29]=2[CH:28]=1>C(=O)=O.CC(C)=O>[O:13]1[CH2:14][CH2:15][O:16][CH:12]1[C:3]1[CH:4]=[C:5]([O:10][CH3:11])[C:6]([O:8][CH3:9])=[CH:7][C:2]=1[CH:33]([C:32]1[CH:27]=[CH:28][C:29]2[O:37][CH2:36][O:35][C:30]=2[CH:31]=1)[OH:34]
To a flame dried four necked round bottom flask (100 mL) were added 2-(2-bromo-4,5-dimethoxyphenyl)-1,3-dioxolane (formula VII; 1.0 g, 0.9934 mole) and anhydrous tetrahydrofuran (25 ml) under nitrogen atmosphere. The flask was cooled to −78° C. in dry ice-acetone bath; n-Butyllithium (5.3 ml, 0.005 mole) was added drop wise with stirring at −78° C. and stirred for 15 minutes. A separate flame dried flask was charged with Piperonal (0.517 g, 1.0034 mole) and dry tetrahydrofuran (6 ml). The Piperonal solution was cannulated to the reaction mixture during 30 minutes and after the addition, reaction mixture was slowly warmed to room temperature and further stirred for 2.5 hours. After the consumption of all bromine compound, as confirmed by TLC (50:50, EtOAc:Hexane), reaction mixture was quenched by the addition of saturated ammonium chloride solution and extracted with ethyl acetate (3×20 ml). All the organic layers were combined, dried over anhydrous sodium sulfate, filtered and concentrated to yield 80% of crude product. The crude product was purified by column chromatography using column of 2 meter length, diameter 2.5 cm and filled with silica gel 60-120 (column chromatographic grade). Finally column eluted with EtOAC:Hexane (50:50), to get pure product (2-(1,3-Dioxolane-2-yl)-4,5-dimethoxy phenyl) (benzo(d)(1,3)dioxol-5-yl)-methanol with 30% yield. The total time required was about 7 hours.
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