Hydrochloric Acid → trans 1-(t-Butyldimethylsilyl)-3-phenylacetyl-4-tritylthio-2-azetidinone

Participants

Reaction Conditions

Reaction Steps

1-t-Butyldimethylsilyl-4-tritylthio-2-azetidinone (18.32 g, 40 mmol) in dry THF (100 ml) was added dropwise under N2 to a cooled (-78° C.) LDA solution [prepared under N2, at -78° C. from dropwise addition of 1.6 M n-BuLi (101.25 ml, 162 mmol) to diisopropyl amine (22.95 ml, 162 mmol) in dry THF (150 ml) and stirred at -78° C. for 30 min]. The mixture was stirred at -78° C. for 30 min and ethyl phenylacetate (15.66 g, 15.12 ml 15.12 ml, 93.6 mmol) in dry THF (50 ml) was added and the reaction mixture was stirred at -78° C. for 2 h. It was poured onto ice-1 N HCl (pH 5-6) and extracted with ether several times. The ether solution was washed with brine and dried (Na2SO4 ). It was evaporated to dryness to give 33.7 g of a crude solid. This was dissolved in ether (10 ml) and triturated with pentane (200 ml). The solid was filtered and washed several times with pentane to give 18.3 g of a white solid (79.6%) mp 141-143. 1Hmr (CDCl3 δ: 7.0-7.6 (20H, m), 4.8 (H, d), 3.7 (H, d), 3.53 (H, s), 3.43 (H, s) 1.5 (9H, s) and 0.3 ppm (6H, s).

Provenance & Evidence