Sodium Bicarbonate → tert-butyl (2S)-2-{[tert-butyl(dimethyl)silyl]oxy}-3-phenoxypropyl{[(2S)-6-(2,2-dimethyl-4-oxo-4H-1,3-benzodioxin-7-yl)-3,4-dihydro-2H-chromen-2-yl]methyl}carbamate

Participants

Reaction Conditions

Reaction Steps

To a degassed solution of tert-butyl (2S)-2-{[tert-butyl(dimethyl)silyl]oxy}-3-phenoxypropyl{[(2S)-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-3,4-dihydro-2H-chromen-2-yl]methyl}carbamate (1.0 g, 1.53 mmol, 1.0 eq.) in toluene (12 mL) were added 2,2-dimethyl-4-oxo-4H-1,3-benzodioxin-7-yl trifluoromethanesulfonate (0.60 g, 1.84 mmol, 1.2 equiv.), dichloro[1,1′-bis(diphenylphosphino)ferrocene] palladium(II) dichloromethane adduct (0.18 g, 0.23 mmol, 0.15 eq.) and saturated sodium bicarbonate (8.0 mL) under argon atmosphere at room temperature. The reaction mixture was allowed to heat up at 80° C. under argon atmosphere for 18 hours. The mixture was then quenched with distilled water (10 mL) and extracted with ethyl acetate (3×10 mL). The combined extracts were washed with brine (20 mL), dried over magnesium sulfate, filtered and concentrated under reduced pressure to afford black oil. Purification by flash chromatography on a silica gel column (5%-15% ethyl acetate/hexanes) yielded the desired product as colorless oil (0.81 g, 76%). 1H NMR (CDCl3) δ7.86 (d, 1 H), 7.27-6.78 (m, 11H), 4.20-3.85 (m, 2H), 3.81-3.40 (m, 4H), 3.37-3.20 (m, 2H), 2.80-2.21 (m, 2H), 1.95-1.84 (m, 1H), 1.64 (s, 7H), 1.39 (s, 9H), 0.81 (s, 9H), 0.020 (s, 6H).

Provenance & Evidence