tert-butyl (2S)-2-formylpyrrolidine-1-carboxylate → (S)-tert-Butyl 2-((1R,2S)-1-hydroxy-2-methylbut-3-en-1-yl)pyrrolidine-1-carboxylate

Beteiligte Stoffe

Reaktionsschritte

To a solution of tert-butyl (2S)-2-formylpyrrolidine-1-carboxylate (10 g, 50 mmol, 1 eq.) in dichloromethane (120 mL, 0.42 M) was added potassium (2Z)-2-buten-1-yltrifluoroborate (9.76 g, 60.2 mmol, 1.2 eq.) followed by tetra-n-butylammonium bromide (3.24 g, 5.02 mmol, 0.1 eq.) and water (60 mL). After 13 hours, the reaction was diluted with dichloromethane (150 mL) and water (150 mL). The aqueous layer was separated and back-extracted with dichloromethane (100 mL). The combined organic layers were washed with aqueous sodium chloride solution (5% wt, 200 mL), washed with water (200 mL), and concentrated in vacuo to afford #9 (˜13 g) as an orange oil, which was used without further purification. 1H NMR (400 MHz, CDCl3) δ 5.61-5.86 (br m, 1H), 4.97-5.09 (m, 2H), 3.80-3.98 (br m, 2H), 3.45-3.67 (br m, 1H), 3.21-3.29 (m, 1H), 2.14-2.26 (m, 1H), 1.80-2.04 (m, 3H), 1.65-1.76 (m, 1H), 1.47 (s, 9H), 1.12 (d, J=6.6 Hz, 3H).

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