Research Article
Synthetic Studies on Potent Marine Drugs: Synthesis and the Crystal Structure of 6-tert-butyl-4-phenyl-4H-chromene-2-carboxylic Acid
Table 2
Condensation of an β,γ-unsaturated α-ketoester 11 with phenol 12 a.
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General conditions: The mixture of AuCl3 (15.2 mg, 0.05 mmol) and AgOTf (38.6 mg, 0.15 mmol) in 1,2-dichloroethane (5 mL) was stirred at room temperature for 0.5 hour and then was added with a β,γ-unsaturated α-ketoester 11 (1.0 mmol) and a phenol 12 (1.0 mmol). The resulting mixture was stirred at reflux for 6 hours. The crude products in 1,2-dichloroethane (5 mL) were filtered through Celite, added with a drop of concentrated sulfuric acid, and stirred at room temperature for 0.5 hour. |