Effective Palladium-Catalyzed Synthesis of Triarylethene-Based Molecules in Aqueous Solution
Yan Zhu, et al
Highly effective and selective Pd-catalyzed coupling reactions of 1,1-dibromo-1-alkenes with various arylboronic acids have been performed in aqueous solution under mild conditions. The method is simple, economic, and practical for the synthesis of triarylethene-based compounds.
General procedure for Pd-catalyzed double coupling between various 1,1-dihalo-
1-alkenes and arylboronic acids without using ligand:
1,1-Dihalo-1-alkene (0.3 mmol) was dissolved in the mixed solvent (PEG-400, 0.5
mL and H2O 1.5 mL), followed by addition of arylboronic acid (0.7 mmol), palladium
acetate (0.012 mmol), potassium phosphate (0.6 mmol), The reaction mixture was
stirred at 40 oC for 24 h. After cooling to room temperature, the mixture was diluted
with water, and the combined aqueous phases were extracted three times with ethyl
acetate. The organic layers were combined, dried over Na2SO4, and concentrated to
yield the crude product, which was further purified by silica gel chromatography,
using petroleum ether and ethyl acetate as eluent to provide the desired product.
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