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

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Reaction Conditions

Reaction Steps

(1S,2R,3S,4R)-3-Amino-bicyclo[2.2.1]heptane-2-carboxylic acid ethyl ester (prepared as described in Example 6k, 0.5 g, 2.7 mmol) was dissolved in methanol (25 mL). Isovaleraldehyde (0.233 g, 2.7 mmol) was added followed by acetic acid (1 mL). The solution continued to stir at 25° C. for 10 min. Sodium cyanoborohydride (0.424 g, 6.75 mmol) was added and the mixture was stirred at 25° C. for 5 h. The mixture was poured into aqueous half-saturated aqueous sodium bicarbonate solution (100 mL). The aqueous layer was extracted with ethyl acetate (2×100 mL). The organic layer was dried over sodium sulfate, filtered, and concentrated in vacuo to afford the crude product, (1S,2R,3S,4R)-3-(3-methyl-butylamino)-bicyclo[2.2.1]heptane-2-carboxylic acid ethyl ester (0.43 g, 1.7 mmol, 63%), as a light yellow oil, which was used in the next step without any further purification. LC-MS (ESI) calcd for C15H27NO2 253.2. found 254.1 [M+H+].

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