反应详情

温度

-78 °C

Diisobutylaluminum hydride (3.72 ml of 0.91M in hexane, 3.38 mmol) is added slowly by syringe to a solution of (3S,4R)-1-(t-butyldimethylsilyl)-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-4-carbomethoxymethyl azetidin-2-one (936 mg, 2.26 mmol) in 25 ml of freshly distilled toluene at -78° C. The resulting solution is stirred at -78° C. for 3 hrs., then quenched by addition of 2.5N hydrochloric acid (5 ml). The resulting mixture is stirred for 2 min., then poured into a separatory funnel containing 100 ml of ether and 50 ml of 1.25N hydrochloric acid saturated with tartaric acid. The organic phase is separated and the aqueous phase is extracted with ether (2×50 ml). The combined organic phases are washed with brine over magnesium sulfate. Removal of solvents in vacuo gives a white solid which is recrystallized from ether-petroleum ether to give (3S,4R)-1-(t-butyldimethylsilyl)-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-4-(2-oxoethyl)-azetidin-2-one. m.p. 115°-116° C.; n.m.r. (CDCl3) δ4.1 (m, 1), δ4.03(m, 1), δ2.7-3.2(m, 3), δ1.23(d, 3, J=6.4), δ1.08(s, 9), δ0.9(s, 9), δ0.25(s, 6), δ0.1(s, 6), δ9.83 (t, 1, J=1.4).

1. custom, then quenched by addition of 2.5N hydrochloric acid (5 ml)
2. stirringThe resulting mixture is stirred for 2 min.
3. additionpoured into a separatory funnel
4. additioncontaining 100 ml of ether and 50 ml of 1.25N hydrochloric acid saturated with tartaric acid
5. customThe organic phase is separated
6. extractionthe aqueous phase is extracted with ether (2×50 ml)
7. washThe combined organic phases are washed with brine over magnesium sulfate
8. customRemoval of solvents in vacuo
9. customgives a white solid which
10. customis recrystallized from ether-petroleum ether