Boron trifluoride etherate → HCID 68863714, compound

Participants

Reaction Steps

A mixture of R-[N,N′-bis(monoisopinocampheylborane)-N,N,N′,N′-tetramethylethylenediamine] (1.25 g, 3.0 mmol) in THF (5 mL) was treated with boron trifluoride etherate, stirred at room temperature for 1.5 hours, and filtered. The filter cake was washed with THF (2.5 mL). Half of the solution containing the free isopinocamphenylborane (1.5 mmol) was cooled to −25° C., treated with a solution of Example 275D (500 mg, 1.25 mmol) in THF (3 mL), stirred at −20° C. for 48 hours, warmed to 0° C., and quenched with methanol (0.5 mL). The solution was treated with 3M NaOH (1.1 mL), followed by 30% H2O2 (0.9 mL) dropwise, stirred for 1 hour at 50° C., cooled to room temperature, extracted with diethyl ether, dried (Na2SO4), filtered, and concentrated. The concentrate was purified by flash column chromatography on silica gel with 30% acetone/hexanes to give 300 mg (57% yield). MS (ESI) m/e 412 (M−H)−; 1H NMR (300 MHz, DMSO-d6) δ 10.02 (s, 1H), 7.69 (m, 1H), 7.63 (dt, 1H), 7.42 (m, 1H), 7.30 (dt, 1H), 7.0 (d, 1H), 6.92 (d, 1H), 4.73 (d, 1H), 3.85 (m, 1H), 2.95 (m, 1H), 2.82 (m, 1H), 2.6 (m, 1H), 1.81 (m, 1H), 1.69 (m, 1H), 0.98 (d, 3H).

Provenance & Evidence