1,5-Diazabicyclo(5,4,0)undec-5-ene → Benzyl 6-(3-methoxycarbonylprop-2-ene-1-yl)-7-oxo-3-phenylsulphinyl-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate

Participants

Reaction Steps

Benzyl 3-chloro-6-(3-methoxycarbonylprop-2-en-1-yl)-7-oxo-3-phenylsulphinyl-1-azabicyclo[3.2.0]heptane-2-carboxylate (68) (0.015 g) was stirred in ethyl acetate (2 ml) at room temperature under argon and treated with 1,5-diazabicyclo[5.4.0]undec-5-ene (0.005 g). After a period of 15 mins. the reaction mixture was washed with brine and dried over sodium sulphate. Removal of the solvent gave a single diastereoisomer of benzyl 6-(3-methoxycarbonylprop-2-ene-1-yl)-7-oxo-3-phenylsulphinyl-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate (69) (0.013 g) as a gum; νmax (CHCl3) 2980, 1795, 1730, 1720, 1660 and 1045 cm-1 ; τ(d6 -acetone) 2.3-2.8 (10H, m, phenyls), 3.12 (1H, dt J 16 and 6 Hz, CH2 -CH=), 4.12 (1H, dt J 16 and 1 Hz, =CH-CO), 4.68 (2H, s, benzyl CH2), 5.72 (1H, ddd J 10, 9 and 6 Hz, C5-H), 5.9-6.3 (1H, m, C6-H), 6.39 (3H, s, OCH3), 6.81 (1H, dd J 18 and 9 Hz, C4-H), 7.25 (1H, dd J 18 and 10 Hz, C4-H) and 6.9-7.4 (2H, m, CH2 -CH=).

Provenance & Evidence