Carbamic acid, [(1R,3S)-3-hydroxycyclopentyl]-, 1,1-dimethylethyl ester (9CI)

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:-10.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of (3-hydroxycyclopentyl)-carbamic acid tert-butyl ester (prepared as described in Tetrahedron 1999, 55, 10815-10834) (1 eq) in DCM (1 M) at −10° C. was added [bis(2-methoxyethyl)amino]sulfur trifluoride (1 eq). The reaction mixture was stirred at −10° C. for 15 min, then the reaction mixture was diluted with DCM, washed with sat. aq. NaHCO3 solution, and back-extracted with DCM (3×). The collected organic phases were dried (Na2SO4), and evaporated under reduced pressure. The crude product was purified by column chromatography on silica gel to afford tert-butyl cis-3-fluorocyclopentylcarbamate, MS (ES) C10H18FNO2 requires: 203 found: 204 (M+H)+. A solution of this intermediate in DCM/TFA (1:1, 0.24 M) was stirred at RT for 30 min and then concentrated under reduced pressure. The resulting crude was used as such in the next step without further purification. MS (ES) C5H10FN requires: 103 found: 104 (M+H)+. washed with sat. aq. NaHCO3 solution back-extracted with DCM (3×) The collected organic phases were dried (Na2SO4) evaporated under reduced pressure The crude product was purified by column chromatography on silica gel

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

Procedure: A mixture of tert-butyl(3-hydroxycyclopentyl)carbamate (800 mg, 3.98 mmol) and Dess-martin reagent (3.6 g, 8.15 mmol) in DCM (20 mL) was stirred at RT overnight. And then, the reaction was quenched by addition of sat. aqueous solution of NaHCO3 and sat. aqueous solution of Na2SO3. The resulting mixture was extracted with DCM (20 mL×3). The combined organic layers were dried over Na2SO4, and then concentrated in vacuo. The residue was purified by silica-gel chromatography to afford tert-butyl(3-oxocyclopentyl)carbamate as a white solid (730 mg). And then, the reaction was quenched by addition of sat. aqueous solution of NaHCO3 and sat. aqueous solution of Na2SO3 The resulting mixture was extracted with DCM (20 mL×3) The combined organic layers were dried over Na2SO4 concentrated in vacuo The residue was purified by silica-gel chromatography