tert-butyl N-(2-fluoro-2-methylcyclopentyl)carbamate

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A 4 M dioxane solution of hydrogen chloride (6.30 mL, 25.2 mmol) was added to a stirred solution of tert-butyl 2-fluoro-2-methylcyclopentylcarbamate (1.0954 g, 5.04 mmol, from Step 4) in dichloromethane (4 mL) at room temperature. After 1.5 h at room temperature, the solvent was evaporated to give 2-fluoro-2-methylcyclopentanamine hydrochloride (740 mg, 96% yield). the solvent was evaporated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (Diethylamino)sulphur trifluoride (2.75 mL, 20.84 mmol) was added to a solution of tert-butyl 2-hydroxy-2-methylcyclopentylcarbamate (2.243 g, 10.42 mmol, from Step 3) in dichloromethane (40 mL) at −78° C. under nitrogen. After 4 h at −78° C., the mixture was quenched with saturated sodium bicarbonate, allowed to warm to room temperature, and extracted with dichloromethane. The dichloromethane phase was concentrated and purified by silica gel chromatography, eluting with 0 to 50% ethyl acetate in hexanes, to give tert-butyl 2-fluoro-2-methylcyclopentylcarbamate as brown oil (1.095 g, 48% yield). 1H NMR analysis indicated approximately 3.5:1 mixture of two diastereomers. the mixture was quenched with saturated sodium bicarbonate extracted with dichloromethane The dichloromethane phase was concentrated purified by silica gel chromatography eluting with 0 to 50% ethyl acetate in hexanes