Triethylamine → t-Butyl 2-hydroxy-2-[(3R,4R)-3-phenylacetamido-4-[(RS)-tetrahydropyran-2-ylcarbonylmethylthio]azetidin-2-on-1-yl]acetate

Participants

Reaction Steps

(3R,4R)-3-Phenylacetamido-4-[(RS)-tetrahydropyran-2-yl-carbonylmethylthio]azetidin-2-one (1.7 g) in 1,2-dichloroethane (20 ml) was successively treated with 0.5M t-butyl glyoxylate in 1,2-dichlorethane (10 ml) and triethylamine (50 mg, 70 μl) and monitored by t.l.c. (ethyl acetate) until no starting material remained. The reaction mixture was concentrated and flash chromatography (70% ethyl acetate in hexane, ethyl acetate) to afford the title compound as a yellow foam (1.9 g, 82%); νmax (CH2Cl3) 3400 (w), 1780, 1736, 1687 cm-1 ; δH (CDCl3) 1.49 (9H, s) overlapping 1.44-1.61 (4H, m), 1.8-2.0 (2H, m), 3.35-3.58 (3H, m), 3.65 (2H, s), 3.81-3.92 (1H, m), 4.01-4.06 (1H, m), 4.28-4.43 (1H, m), 4.99, 5.00, 5.07 (together 1H, 3d, J4.7 Hz), 5.21, 5.32, 5.33 (together 1H, 3d, J6.8, 7.7, 7.6 Hz), 5.42, 5.50 (together 1H, 2dd, J4.8, 8.7 Hz, 6.35, 6.36, 6.61 (together 1H, 3d, J8.7 Hz) and 7.27-7.38 (5H, m).

Provenance & Evidence