Potassium Phosphate, Tribasic → Ethyl 6-chloro-7-(4-(4-chloro-2-cyclopropylphenethylcarbamoyl)phenoxy)chroman-4-carboxylate

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Reaction Steps

To a stirred suspension of ethyl 7-(4-(2-bromo-4-chlorophenethylcarbamoyl)phenoxy)-6-chlorochroman-4-carboxylate (129 mg; 0.22 mmol) in 2 mL toluene was added successively water (0.1 mL), potassium phosphate (138 mg; 0.65 mmol), tricyclohexylphosphine (24 mg; 0.087 mmol), and cyclopropylboronic acid (0.435 mmol) at ambient temperature with stirring. A balloon of nitrogen with a three-way purge valve was attached, and the flask was evacuated and refilled five times with nitrogen. Palladium (II) acetate (10 mg; 0.043 mmol) was added, and again the flask was evacuated and refilled five times with nitrogen. The mixture was stirred in an oil bath set to 100° C. under the nitrogen balloon. After 4 hours the mixture was cooled to ambient temperature. The mixture was diluted with 10 mL EtOAc and 5 mL water. The mixture was transferred to a separatory funnel and after shaking, the organic layer was separated, dried over sodium sulfate and evaporated to give a brown oil. This material was purified by silica gel chromatography on a Biotage 25S column, eluting with 75/25 hexane/EtOAc to provide 83 mg of ethyl 6-chloro-7-(4-(4-chloro-2-cyclopropylphenethylcarbamoyl)phenoxy)chroman-4-carboxylate as a colorless oil. MS (apci, pos) m/z=554.

Provenance & Evidence