Isopropanol → Hexahydro-2H-pyrrolo[3,4-d]oxazol-2-one

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Reaction Steps

A solution of tert-butyl 3-[(tert-butoxycarbonyl)amino]-4-[(methylsulfonyl)oxy]pyrrolidine-1-carboxylate (850 mg) in dichloroethane (50 mL) was refluxed overnight, evaporated and the resulting residue purified on a Biotage Horizon® system (silica, gradient 10-15% methanol in dichloromethane) to yield a racemic mixture of tert-butyl 2-oxohexahydro-5H-pyrrolo[3,4-d][1,3]oxazole-5-carboxylate which was resolved by chiral HPLC (Chiralcel OJ column, isopropyl alcohol/hexptane 13:87) to yield fast moving isomer A and slow moving isomer B. Each of isomer A and isomer B was treated with trifluoroacetic acid/methylene chloride (1:1) and passed through ion exchange resin (Strata-X-C™) and eluted with methanol containing 5% ammonium hydroxide to yield hexahydro-2H-pyrrolo[3,4-d][1,3]oxazol-2-one isomer A2 and isomer B2, respectively.

Provenance & Evidence