HCID 66774307, compound → HCID 66688039, compound

Participants

Reaction Steps

To a solution of 2-cyclopropylmethyl-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester (4 g, see example 64 and 65) in THF (100 mL) was added borane-methylsulfide complex (8.9 mL of a 2M solution in THF) dropwise via syringe. The reaction mixture was heated for 4 hours to 80° C. and was then cooled to RT. The THF was removed in vacuo and the residue was then diluted with water and DCM. The phases were separated and the aqueous phase was extracted with further DCM (2×50 mL). The combined organic layers were washed with saturated aqueous sodium bicarbonate solution, brine and dried over sodium sulfate. Filtration of the drying agent and evaporation in vacuo to dryness afforded the crude 2-cyclopropylmethyl-2-hydroxymethyl-pyrrolidine-1-carboxylic acid tert-butyl ester (3.7 g) to which was added Dess-Martin periodinane solution (32.6 mL of a 15% solution in DCM, CAS [87413-09-0]) and the reaction mixture was stirred for 5 hours at RT. The reaction was quenched with 10 mL of saturated aqueous sodium thiosulfate solution and stirred for a further 20 minutes. The phases were separated and the DCM layer was washed with saturate aqueous sodium bicarbonate solution. The aqueous layers were back extracted with further DCM and the combined DCM layers were dried over sodium sulfate, filtered and reduced to dryness in vacuo to afford the desired 2-cyclopropylmethyl-2-formyl-pyrrolidine-1-carboxylic acid tert-butyl ester (2.59 g, MS (ES+): 254.3 (M+H), as a brown oil).

Provenance & Evidence