J. Pitlik et al., SYNTHESIS AND TRANSFORMATIONS OF 3-VINYLCEPHALOSPORINS .6. REACTIONS OF CEPHALOSPORIN PHOSPHORANES WITH BIFUNCTIONAL CARBONYL-COMPOUNDS, Journal of the Chemical Society. Perkin transactions. I, (20), 1994, pp. 3043-3046
Cephalosporin C-3-phosphoranes have been converted into the correspond
ing 3-alkenylcephems and novel tricyclic derivatives on treatment with
different bifunctional carbonyl compounds. The effect of substituents
on the product ratio has been examined. The stereoselectivity of the
ring-closure is explained on the basis of theoretical considerations.