Benzyl Alcohol → 8-Fluoro-5-methoxychroman-3-y-carbamic acid benzyl ester

Participants

Reaction Steps

8-Fluoro-5-methoxychroman-3-yl carboxylic acid (1.12 g; 85.0 mmol), diphenyl phosphoryl azide (1.3 mL; 5.9 mmol) and toluene (10 mL) were mixed in a three-necked round-bottom flask (50 mL) under nitrogen. Triethylamine (0.83 mL; 5.9 mmol) was added and clear solution was stirred at 100° for 2 h. Benzylalcohol (0.61 mL; 5.9 mmol) was added in one portion and the stirring continued at 90° C. for 17 h. The volatiles were evaporated and the residue was taken up in toluene (25 mL). After washing with 10% acetic acid (1×30 mL) and 2M ammonia (1×30 mL) the solution was dried (MgSO4), filtered and concentrated in vacuo to give a brown oil. Flash-chromatography of the crude product on a silica column eluted with ethyl acetate /toluene (3:97) afforded compound as an oil (contaminated with 2% unreacted isocyanate according to GC).

Provenance & Evidence