3-Methylbutanal → (1S,2R,3S,4R)-3-isobutylamino-bicyclo[2.2.1]heptane-2-carboxylic acid ethyl ester

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Reaction Conditions

Reaction Steps

Isovaleraldehyde (0.374 mL, 4.10 mmol) and 10 drops glacial acetic acid were added sequentially to a solution of (1S,2R,3S,4R)-3-amino-bicyclo[2.2.1]heptane-2-carboxylic acid ethyl ester (prepared as described in Example 6k, 0.750 g, 4.09 mmol) in methanol (12 mL) at 25° C. Sodium cyanoborohydride (0.643 g, 10.2 mmol) was added, and the reaction mixture was stirred at 25° C. for 2 h, and then was partitioned between half-saturated aqueous sodium bicarbonate solution (150 mL) and ethyl acetate (2×150 mL). The organic layers were dried over sodium sulfate, filtered and concentrated in vacuo to afford the desired product, (1S,2R,3S,4R)-3-isobutylamino-bicyclo[2.2.1]heptane-2-carboxylic acid ethyl ester, as a clear oil, which was used in the next step without any further purification.

Provenance & Evidence