Ethyl 7-(4-(tert-butoxycarbonyl)-2-nitrophenoxy)-6,8-dichlorochroman-4-carboxylate → Ethyl 7-(2-amino-4-(tert-butoxycarbonyl)phenoxy)-6,8-dichlorochroman-4-carboxylate

Participants

Reaction Steps

To a mixture of ethyl 7-(4-(tert-butoxycarbonyl)-2-nitrophenoxy)-6,8-dichlorochroman-4-carboxylate (2.70 g, 5.27 mmol) in 25 mL of THF and 25 mL of saturated ammonium chloride was added zinc dust (3.45 g, 52.7 mmol) under argon. After 1 hour at ambient temperature, the reaction was diluted with ethyl acetate and filtered. The biphasic filtrate was separated and the organic layer was washed with brine. The organic layer was dried over sodium sulfate, filtered and concentrated. The crude product was dissolved in dichloromethane, concentrated onto silica gel and purified by flash column chromatography, eluting with 20% ethyl acetate in hexanes to give ethyl 7-(2-amino-4-(tert-butoxycarbonyl)phenoxy)-6,8-dichlorochroman-4-carboxylate (2.20 g, 86.5% yield) as a white foam. MS (ESI) m/z=482 (M+H).

Provenance & Evidence