反应详情

温度

-35 °C

To a stirred yellow solution of ethyl 6-(2-ethoxy-2-oxoacetyl)-7-iodo-5-methylpyrazolo[1,5-a]pyrimidine-2-carboxylate (6.4 g, 14.84 mmol) in anhydrous toluene (300 mL) was added 1.1M (R)-1-methyl-3,3-diphenylhexahydropyrrolo[1,2-c][1,3,2]oxazaborole/toluene (5.40 mL, 5.94 mmol). The mixture was cooled to −35° C. and a solution of 50% catechoborane/toluene (5.09 mL, 20.78 mmol) was added over 10 min. After 30 min, the reaction mixture was slowly warmed to −15° C. and stirred for additional 2 h, then diluted with EtOAc (600 mL) and sat. Na2CO3 (100 mL). The mixture was stirred vigorously for 30 min, and the organic phase washed with sat Na2CO3 (2×100 mL), dried (Na2SO4), filtered, concentrated and the residue was purified by silica gel chromatography (5-100% EtOAc/hexane) to afford desired (S)-ethyl 6-(2-ethoxy-1-hydroxy-2-oxoethyl)-7-iodo-5-methylpyrazolo[1,5-a]pyrimidine-2-carboxylate (5.3 g, 12.23 mmol, 82% yield) as off-white solid. 1H NMR (500 MHz, CDCl3) δ: 7.33 (s, 1H), 5.75 (d, J=2.4 Hz, 1H), 4.52 (qd, J=7.1, 1.1 Hz, 2H), 4.38-4.29 (m, 2H), 3.59 (d, J=2.4 Hz, 1H), 2.63 (s, 3H), 1.48 (t, J=7.2 Hz, 3H), 1.27 (t, J=7.2 Hz, 3H). LCMS (M+H)=434.2.

1. temperaturethe reaction mixture was slowly warmed to −15° C.
2. stirringThe mixture was stirred vigorously for 30 min
3. washthe organic phase washed
4. dry with materialdried (Na2SO4)
5. filtrationfiltered
6. concentrationconcentrated
7. customthe residue was purified by silica gel chromatography (5-100% EtOAc/hexane)