Cesium carbonate → 4-[1-(4-Tert-butyl-phenyl)-piperidin-4-yl]-butyric acid methyl ester

Participants

Reaction Steps

A mixture of palladium (II) acetate (63 mg; 0.28 mmol), (±)-2,2′-bis-diphenylphosphanyl-[1,1′]binaphthalenyl (258 mg; 0.41 mmol) and cesium carbonate (1.30 g; 4.00 mmol) in dioxane (3 mL) is placed in an ultrasonic bath for 45 minutes. 4-Piperidin-4-yl-butyric acid methyl ester hydrochloride (415 mg; 2.0 mmol, prepared in accordance with Example 131) and 1-bromo-4-tert-butyl-benzene (426 mg; 2.00 mmol) are then added and the reaction mixture is stirred for 2 hours under reflux. New catalyst solution (prepared as above from palladium (II) acetate (63 mg; 0.28 mmol), (±)-2,2′-bis-diphenylphosphanyl-[1,1′]binaphthalenyl (258 mg; 0.41 mmol), cesium carbonate (1.30 g; 4.00 mmol) and dioxane (3 mL) is prepared with the aid of an ultrasonic bath and added to the reaction mixture. After stirring under reflux for 3 hours, the mixture is diluted with ethyl acetate and is filtered. The filtrate is concentrated under high vacuum and the obtained residue is purified by column chromatography on silica gel (hexanes/dichloromethane 50:50 v/v to 100) to afford the desired compound (385 mg; 1.21 mmol).

Provenance & Evidence