Triethylamine → tert-Butyl 4-(5-bromo-2,3-dihydro-1H-inden-2-yl)piperazine-1-carboxylate

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Reaction Conditions

Reaction Steps

In a 100 mL round bottom flask, tert-butyl di(prop-2-en-1-yl)carbamate (0.74 mL, 3.4 mmol) was dissolved in dichloromethane (10 mL). The solution was cooled to −78° C. To above solution was bubbled ozone for 15 min. The solution turned into light blue and the color stayed. To above solution was bubbled nitrogen to remove excess ozone until the solution turned into colorless. To above solution was added (5-bromo-2,3-dihydro-1H-inden-2-amine (1.0 g, 3.4 mmol), triethylamine (0.48 mL, 3.4 mmol) followed by sodium triacetoxyborohydride (4.3 g, 20 mmol). The reaction was allowed to warm up to room temperature and stirred at this temperature overnight. HPLC-MS showed product was formed as major peak. To above solution was added water (5 mL), extracted with dichloromethane (10 mL×3). The organic phase was dried over MgSO4, filtered and concentrated. The product was obtained as white solid after purification by flash column chromatography. LC-MS (IE, m/z): 381.2 [M+1]+. 1H NMR (500 MHz, CDCl3, δ in ppm): 7.30 (1H, s), 7.25 (d, J=8.0 Hz, 1H), 7.03 (d, J=8.0 Hz, 1H), 2.0-4.0 (m, 13H), 1.5 (s, 9H).

Provenance & Evidence