反应详情

A solution of ethyl 5-(4-(but-3-en-1-yl)-4-methylpiperidin-1-yl)-6-(2-methoxy-2-oxoacetyl)-7-methylimidazo[1,2-a]pyridine-2-carboxylate (0.44 g, 1.00 mmol, 1 equiv) and R-5,5-diphenyl-2-methyl-3,4-propano-1,3,2-oxazaborlidine (1.59 mL of a 1 M solution in toluene, 1.59 mmol, 1.6 equiv) in toluene (10 mL) was cooled to −30° C. (IPA/dry ice). Catecholborane (0.34 mL, 1.59 mmol, 1.6 equiv) was added and the reaction was stirred at −15° C.-30° C. for 3 h. The reaction was then added to 10% K2CO3 and extracted with ether (×3). The combined ether extracts were dried (MgSO4) and concentrated in vacuo. The crude product was purified by flash column chromatography (30-100% EtOAc/hex) to provide the product (0.51 g, ˜100%) as a viscous colorless oil. NMR shows contamination with a CBS byproduct accounting for extra mass. 1H NMR (500 MHz, CDCl3) δ 8.26 (s, 1H), 7.40 (s, 1H), 5.98-5.84 (m, 1H), 5.61 (d, J=11.0 Hz, 1H), 5.17-4.98 (m, 2H), 4.55-4.46 (m, 2H), 3.81 (s, 3H), 3.61 (t, J=10.9 Hz, 2H), 3.11-2.94 (m, 4H), 2.44 (d, J=0.9 Hz, 3H), 2.18-2.09 (m, 2H), 1.82-1.53 (m, 4H), 1.50-1.44 (m, 3H), 1.16 (s, 3H); LCMS (ESI, M+1): 444.25.

1. extractionextracted with ether (×3)
2. dry with materialThe combined ether extracts were dried (MgSO4)
3. concentrationconcentrated in vacuo
4. customThe crude product was purified by flash column chromatography (30-100% EtOAc/hex)