(3S,4R)-1-(t-butyldimethylsilyl)-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-4-carbomethoxymethylazetidin-2-one → (3S,4R)-1-(t-butyldimethylsilyl)-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-4-(2-oxoethyl)azetidin-2-one

HRID 648687Notes

Reaction equation

[H-].C([Al+]CC(C)C)C(C)C.[Si:11]([N:18]1[C@H:21]([CH2:22][C:23](OC)=[O:24])[C@@H:20]([C@H:27]([O:29][Si:30]([C:33]([CH3:36])([CH3:35])[CH3:34])([CH3:32])[CH3:31])[CH3:28])[C:19]1=[O:37])([C:14]([CH3:17])([CH3:16])[CH3:15])([CH3:13])[CH3:12]>C1(C)C=CC=CC=1>[Si:11]([N:18]1[C@H:21]([CH2:22][CH:23]=[O:24])[C@@H:20]([C@H:27]([O:29][Si:30]([C:33]([CH3:36])([CH3:35])[CH3:34])([CH3:31])[CH3:32])[CH3:28])[C:19]1=[O:37])([C:14]([CH3:17])([CH3:15])[CH3:16])([CH3:13])[CH3:12]

Participants

Conditions

Temperature: -78 °C

Procedure

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).

Workup

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

Sources & evidence

ORD record: ord-744ca5d13f3c40f5af1ad49fdbeb3166
Source dataset: uspto-grants-1988_04
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04736025

Reaction notes

Loading…