Boron trifluoride etherate → 3-Bromo-7-tert-butoxy-1-nitronaphthalene

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 1-amino-2-bromo-6-tert-butoxy-4-nitronaphthalene, as described above in Step F, (2.40 g, 7.08 mmol) in CH2Cl2 (150 mL), at −15° C., was added BF3.OEt2 (1.35 mL, 10.6 mmol). To this mixture was added a solution of 90% tert-butyl nitrite (1.12 mL, 8.49 mmol) in CH2Cl2 (9 mL), dropwise. The reaction mixture was stirred at −15° C. for 1 hour, then 50 wt % H3PO2 (9.34 mL, 70.8 mmol) and CuO2 (50 mg, 0.349 mmol) were added and the resulting mixture was stirred vigorously at 0° C. for 40 min. The mixture was partitioned between saturated aqueous Na2CO3 (75 mL) and CH2Cl2 (150 mL). The aqueous layer was extracted further with CH2Cl2 (150 mL). The combined organic extracts were dried over Na2SO4, filtered, and concentrated in vacuo. The crude product was purified by flash column chromatography on silica, eluting with a gradient of hexane—0% to 8% diethyl ether to yield the titled compound.

Provenance & Evidence