Sodium Bicarbonate → 1,1-Dimethylethyl (1S)-1-[[(1,1-dimethylethoxy)carbonyl]amino]-4-oxo-2-cyclopentene-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

Add 2,2,6,6-tetramethyl-1-piperidinyloxy (free radical) (TEMPO) (0.84 g, 5.3 mmol) and KBr (0.63 g, 5.3 mmol, in 2 mL of water) to a solution of (1S,3R)-1-(tert-butoxycarbonylamino)-1-(tert-butoxycarbonyl)-3-hydroxycyclopent-4-ene (20 g, 66.8 mmol) in MTBE (200 mL). Cool the reaction mixture to 0° C. and add a solution of NaOCl (3.14%, 240 g, 100 mmol) containing NaHCO3 (8.4 g) dropwise, keeping the temperature below 5° C. Stir the reaction 1 hour at 0° C. and allow to warm to room temperature. Separate the layers and extract the aqueous layer with MTBE (2×200 mL). Wash the combined organic layers with 200 mL of 1N HCl solution containing 2.21 g of KI followed by 10% Na2SO3 solution (200 mL). Wash the organic layer with water (2×200 mL) and concentrate to dryness under vacuum. Dissolve the crude product in MTBE (60 mL) at 50° C. and crystallize by addition of heptane (200 mL) over 1 h. Cool the mixture was cooled to 0° C. over 2 hours and then filter. Wash the filter cake with 100 mL of cold heptane:MTBE (65:35) and vacuum dry to give 16.99 g (89% yield) of the title compound as a white solid.

Provenance & Evidence