Collect. Czech. Chem. Commun. 1993, 58, 1607-1623

Nucleophilic Vinylic Substitution on α-Tosyloxymethylene Lactones

Ctibor Mazal and Jaroslav Jonas

Department of Organic Chemistry, Masaryk University, 611 37 Brno, Czech Republic


Sodium salt of 3-hydroxymethylenetetrahydro-2H-pyran-2-one (V), obtained by Claisen condensation of δ-valerolactone with ethyl formate, was converted into its sulfonates and carboxylates IV, VII - X, which were obtained either as pure E-isomers or as mixtures of E- and Z-isomers; the mixtures were chromatographically separated. Substitution reaction of α-tosyloxymethylene lactones II, III and IV with aromatic thiols, azide anion, secondary amines and sodium enolates XI, XII and V was studied. The stereochemical outcome of this substitution is discussed from the viewpoint of mechanism of nucleophilic vinylic substitution (SNV).