反应详情

After stirring for 30 min, a solution of cis-tert-butyl 3-(2-acetamido-1-(tert-butylamino)-1-oxohex-5-en-2-yl)cyclobutyl(benzyl)carbamate (5.34 g, 10.5 mmol), chloro-1,5-cyclooctadiene iridium(I) dimer (212 mg, 0.32 mmol, 3 mol %) and 1,2-bis(diphenylphosphino)ethane (252 mg, 0.63 mmol, 6 mol %) in dichloromethane (50 mL) was cooled to 0° C. and carefully treated with 4,4,5,5-tetramethyl-[1,3,2]dioxaborolane (3.1 mL, 21.1 mmol, 2 eq) over 5 min. After slowly warming to room temperature and stirring overnight, the reaction was poured into water and extracted with ethyl acetate (3×). The combined organic phase was washed with saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate, filtered and concentrated. Purification by flash column chromatography (silica gel, 10-40% ethyl acetate in heptane) gave cis-tert-butyl 3-(2-acetamido-1-(tert-butylamino)-1-oxo-6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hexan-2-yl)cyclobutyl(benzyl)carbamate (4.8 g, 7.83 mmol, 74%). ESI MS found for C34H56BN3O6 m/z [614.2 (M+1), 636.2 (M+23)].

1. stirringstirring overnight
2. extractionextracted with ethyl acetate (3×)
3. washThe combined organic phase was washed with saturated aqueous sodium chloride
4. dry with materialdried over anhydrous magnesium sulfate
5. filtrationfiltered
6. concentrationconcentrated
7. customPurification by flash column chromatography (silica gel, 10-40% ethyl acetate in heptane)