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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