反应详情

温度

0 °C

To a suspension of copper(I) iodide (2 mg) in 1 mL of anhydrous ether at 0°C. was added methylmagnesium bromide (0.106 mL of a 3.0 M solution in ether, 0.319 mmol, 1.00 equiv). Then enone 13 (149 mg, 0.319 mmol) in 2 mL of anhydrous ether was added slowly to the stirring cuprate mixture at a temperature maintained below 5° C., and upon completion of the addition, the reaction mixture was stirred at 0° C. for 3 h before quenching with a 4:1 mixture of saturated aqueous NH4Cl/NH4OH. The resultant biphasic mixture was extracted with ether, dried over Na2SO4, and concentrated under diminished pressure. Purification by flash column chromatography (silica gel, hexanes/ethyl acetate, 9:1) afforded 36 mg (30%) of the desired conjugate addition product as a white solid. 1H NMR (400 MHz, CDCl3) δ0.22 (s, 6H, Si(CH3)2), 1.00 [m, 18H, 3,3,5-CH3 and SiC(CH3)3 ], 1.50 (dd, 2H, J=15.1, 6.5 Hz, 4-Hz, 4-H), 2.02 (m, 1H, 5-H), 2.14 and 2.23 (ABq, 2H, JAB =12.0 Hz, 6-H), 2.42 (dd, 1H, J=10.4, 6.4 Hz, 2-H), 2.88 and 2.89 (d of ABq, 2H, JAB =12.0 Hz, JA =10.4 Hz, JB =6.3 Hz, benzylic-CH2), 3.82 (s, 3H, OCH3), 6.65 (s, 1H, 6'-H), 6.92 ppm (s, 1H, 3'-H).

1. temperaturemaintained below 5° C.
2. additionupon completion of the addition
3. custombefore quenching with a 4:1 mixture of saturated aqueous NH4Cl/NH4OH
4. extractionThe resultant biphasic mixture was extracted with ether
5. dry with materialdried over Na2SO4
6. concentrationconcentrated under diminished pressure
7. customPurification by flash column chromatography (silica gel, hexanes/ethyl acetate, 9:1)
8. customafforded 36 mg (30%) of the desired
9. additionconjugate addition product as a white solid