反应详情

A mixture of 13.93 grams (42.4 mmol, 1.0 eq) of boronate 9 and 27.2 grams (127 mmol, 3.0 eq) of NaIO4 in 126 mL of dry THF was stirred in a 250 mL round bottom flask at room temperature. To this heterogenous mixture was added 42 mL of AcOH (0.5 M). The mixture was warmed to 45° C. and stirred vigorously until complete by TLC (1:1 hexanes:EtOAc). Upon completion (˜65 hours) the mixture was diluted with CH2Cl2 and washed with H2O. The aqueous layer was extracted twice more with CH2Cl2 and the combined organic layers were washed with aqueous Na2S2O3 and then dried over MgSO4. After concentration, the product was purified by filtering through a plug of silica gel with hexane (elutes impurities) followed by EtOAc (elutes product) to give 8.56 grams (81%) of 10 as a colorless oil which is a mixture of boronate esters, Rf 0.20-0.50 (1:1 hexane:EtOAc). 1H-NMR (500 MHz, CDCl3): 8.19 (1H, m), 7.82 (1H, m), 7.61 (1H, m), 7.41 (1H, m), 4.96 (1H, m), 1.64 (3H, m), 0.19 (9H, m). 13C-NMR (500 MHz, CDCl3): 151.45, 137.26, 132.98, 127.65, 126.45, 111.05, 85.85, 31.43, 25.84, 0.41. IR (cm−1): 2961 (w), 2164 (w), 1597 (w), 1442 (m), 1345 (s), 1248 (m), 915 (w), 842 (s), 759 (m), 701 (w). HRMS (EI) calcd. for C13H19BO2Si: 246.1247. found: 245.1173 (M-1).

1. temperatureThe mixture was warmed to 45° C.
2. washwashed with H2O
3. extractionThe aqueous layer was extracted twice more with CH2Cl2
4. washthe combined organic layers were washed with aqueous Na2S2O3
5. dry with materialdried over MgSO4
6. concentrationAfter concentration
7. customthe product was purified
8. filtrationby filtering through a plug of silica gel with hexane (elutes impurities)