Trifluoromethanesulfonate → HCID 131721502, compound

Participants

Reaction Conditions

Reaction Steps

A solution of (tetrahydrofuran-2-yl)tri-n-butylstannane (J. S. Sawyer, A. Kucerovy, T. L. MacDonald, and G. J. McGarvey, J. Amer. Chem. Soc., 1988, 110, 842) (3.0g, 8.30 mmol) in THF (20ml) was cooled to -78° C. n-Butyl lithium (6.23ml of a 1.6M solution in hexane, 9.97mmol) was then added and the solution was stirred for 15 min. at -78° C. A second flask containing copper (I) bromide.dimethyl sulphide complex (0.854g, 4.14mmol) suspended in a mixture of dimethyl sulphide (15ml) and THF (30ml) was then cooled to -78° C. The α-lithiotetrahydrofuran species was transferred via a cannula to the suspension of copper bromide at -78° C. The red-brown homogeneous solution was stirred for 30 min. at -78° C. A third flask containing a solution of diphenylmethyl 7-phenylacetamido-3-triflyloxyceph-3-em-4-carboxylate (V. Farina, S. R. Baker, and S. I. Hanck, J. Org. Chem., 1989, 54, 4962) (1.9g, 3.0mmol) in a mixture of N-methylpyrrolidinone (20ml) and THF (50ml) was then cooled to -78° C. The cuprate species was transferred via a cannula to the solution of triflate at -78° C. The reaction mixture was stirred for 1h at -78° C. then quenched by the addition of saturated aq. ammonium chloride (30ml). The resulting mixture was allowed to warm to room temperature then diluted with water (100ml) and extracted with ethyl acetate (100ml, 30ml). The combined organic phases were washed with water, brine, then dried over magnesium sulphate. After removal of the solvents under reduced pressure the crude reaction product was purified by flash chromatography on silica gel using 10-30% ethyl acetate/methylene dichloride as eluent. After elution of the 3-n-butylcephem, the title compound was obtained as a mixture of diastereoisomers of the Δ2 and Δ3 cephems (1.014g, 61%).

Provenance & Evidence