Hydrochloric Acid → Diphenylmethyl (4R, 6R, 7R)-3(1-hydroxybut 3enyl)7phenylacetamidoceph-2em-4carboxylate

Participants

Reaction Steps

via the Grignard reagent. Allylmagnesium chloride (2M in diethyl ether, 4.0 ml, 8 mmol) was added to a solution containing diphenylmethyl (4R, 6R, 7R)-3-formyl-7-phenylacetamidoceph-2-em-4-carboxylate (0.5 g, 11.0 mmol) and lithium chloride (0.35 g, 8 mmol) in tetrahydrofuran (5 ml) at −70° C. After 20 minutes at −70° C., hydrochloric acid (1M, 10 ml, 10 mmol) was added. Ethyl acetate was added and the organic layer was separated, washed with brine, dried (MgSO4), and evaporated. The resulting oil was purified by chromatography (20% to 60% ethyl acetate in hexane, silica gel) giving; first the title compound S-diastereomer, 90 mg (17%), dH (CDCl3) 2.18 (1H, dt, J 15 Hz and 8 Hz), 2.36 (1H, dt, J 17 and 5 Hz), 3.54 (2H, ABq), 4.18 (1H, m), 4.95-5.15 (4H, m), 5.55-5.7 (2H, m), 6.11 (1H, d, J 9 Hz), 6.36 (1H, s), 6.89 (1H, s), 7.3-7.4 (15H, m), and second; the title compound R-diastereomer, 250 mg (45%), dH (CDCl3) 2.28 (2H, t, J 7 Hz), 3.62 (2H, ABq), 4.15 (1H, t, J 7 Hz), 4.95-5.2 (4H, m), 5.5-5.65 (2H, m), 6.16 (1H, d, J 9 Hz), 6.20 (1H, s), 6.89 (1H, s), 7.3-7.4 (15H, m).

Provenance & Evidence