Methyl iodide → Ethyl 2-allyl-2-(tert-butoxycarbonyl(methyl)amino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate

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Reaction Conditions

Reaction Steps

Ethyl 2-allyl-2-(tert-butoxycarbonylamino)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexanoate (0.64 g, 1.50 mmol) was dissolved in THF (5 mL) and cooled to 0° C. NaHMDS (1 M solution in THF, 2.5 mL, 2.5 mmol) was added dropwise and the reaction was stirred for 20 min. Methyl iodide (0.47 mL, 7.5 mmol) was added and the reaction was warmed to room temperature and stirred overnight. The reaction was quenched with saturated NH4Cl solution (5 mL), diluted with ethyl acetate, washed successively with saturated sodium bicarbonate solution and saturated aqueous sodium chloride, dried over MgSO4, and concentrated in vacuo. The residue was chromatographed on silica gel eluting with 2-25% ethyl acetate in heptane to afford the desired product (0.518 g, 79%). Rf 0.53 (30% ethyl acetate in heptane). 1H NMR (CDCl3, 300 MHz) δ 5.78-5.62 (m, 1H), 5.15-5.03 (m, 2H), 4.12 (q, J=9.0 Hz, 2H), 2.90 (s, 3H), 2.89-2.81 (m, 1H), 2.58-2.51 (m, 1H), 1.94-1.83 (m, 1H), 1.76-1.66 (m, 1H), 1.54-1.08 (m, 29H), 0.77 (t, J=8.0 Hz, 2H). ESI MS found for C23H42B1N1O6 m/z [440.2 (M+1)].

Provenance & Evidence