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

Reaction equation

[C:1]([Si:5]([CH3:8])([CH3:7])Cl)([CH3:4])([CH3:3])[CH3:2].[Si:9]([N:16]1[C@H:19]([CH2:20][C:21]([O:23][CH3:24])=[O:22])[C@@H:18]([C@H:25]([OH:27])[CH3:26])[C:17]1=[O:28])([C:12]([CH3:15])([CH3:14])[CH3:13])([CH3:11])[CH3:10].C(N(CC)CC)C>>[Si:9]([N:16]1[C@H:19]([CH2:20][C:21]([O:23][CH3:24])=[O:22])[C@@H:18]([C@H:25]([O:27][Si:5]([C:1]([CH3:4])([CH3:3])[CH3:2])([CH3:8])[CH3:7])[CH3:26])[C:17]1=[O:28])([C:12]([CH3:15])([CH3:14])[CH3:13])([CH3:11])[CH3:10]

Participants

Reactant 3

HCID 8471Triethylamine

HCID 28928tert-Butyldimethylsilyl chloride

HCID 13104628(3S,4R)-1-(t-butyldimethylsilyl)-3-[(R)-1-hydroxyethyl]-4-carbomethoxymethylazetidin-2-one

Product 1

HCID 13104631(3S,4R)-1-(t-butyldimethylsilyl)-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-4-carbomethoxymethylazetidin-2-one

Procedure

t-Butyldimethylchlorosilane (940 mg, 6.25 mmol) is added in one portion to a solution of (3S,4R)-1-(t-butyldimethylsilyl)-3-[(R)-1-hydroxyethyl]-4-carbomethoxymethylazetidin-2-one (1.88 g, 6.25 mmol) and triethylamine (1.27 g, 6.25 mmol) in 15 ml of anhydrous diemthylformamide at 0° C. After 15 min. at 0° C. the cooling bath is removed and the reaction mixture is stirred at room temperature for 24 hrs. Ether (100 ml) is added and the mixture is filtered, then washed with 2.5 N hydrochloric acid (20 ml), water (3×20 ml) and brine. The organic phase is dried over magnesium sulfate, then concentrated in vacuo. The residue is chromatographed on silica gel (7:3 petroleum ether:ether) to yield (3S,4R)-1-(t-butyldimethylsilyl)-3-[(R)-1-(t-butyldimethylsilyloxy)ethyl]-4-carbomethoxymethylazetidin-2-one. n.m.r. (CDCl3) δ4.1(m,2), δ3.68(S,3), δ3.03(dd,1,J=4.3,2.7), δ2.8(ABq,2), δ1.17(d,3,J=6.6), δ0.98(s,9), δ0.89(s,9), δ0.23(s,6), δ0.1(s,6).