tert-Butanol → Tert-butyl 5-fluoro-2-nitrophenylcarbamate

Participants

Reaction Conditions

Reaction Steps

A flame-dried pressure vessel was charged with 5-fluoro-2-nitrobenzoic acid 118 (5.00 g, 27.0 mmol) and dry t-butyl alcohol (50 mL). To this solution were successively added N,N-di-isopropyl-N-ethylamine (5 mL) and diphenylphosphorylazide (6.42 mL, 29.7 mmol). The vessel was closed with teflon cap and the mixture was heated at 90° C. for 2 h. It was then allowed to cool to r.t. over 16 h. The solvent was removed in vacuo and the residue was partitioned between EtOAc and H2O. The aqueous layer was extracted with fresh EtOAc and the combined organic layers were washed with HCl 1N, sat. NaHCO3, brine, dried over MgSO4, filtered and concentrated. The resulting yellow oil was purified by flash chromatography on silica gel using EtOAc/hexanes (10:90) as an eluent, affording the title compound 119 (6.03 g, 87% yield) as light yellow crystals. LRMS: (m/z): 279.3 (M+Na+).

Provenance & Evidence