反应详情

温度

-78 °C

Diisobutylaluminum hydride (3.72 ml of 0.91 M 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 2.5 N 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 1.25 N 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 and dried 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 2.5 N 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 1.25 N 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
8. dry with materialdried over magnesium sulfate
9. customRemoval of solvents in vacuo
10. customgives a white solid which
11. customis recrystallized from ether-petroleum ether