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Sodium salt of 3-hydroxymethylenetetrahydro-2 H -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 (S N V).

A simple, general and highly stereoselective synthesis of 1-dialkoxylboryl-1,3-dienes that involves a palladium (0) catalyzed cross-coupling reaction of the boronic ester 4 derived from (E)-2-bromoethenylboronic acid and 2,2-dimethyl-1,3-propanediol with various alkenylzinc chlorides is described.

In a one-pot reaction, transition metal substituted polyoxomolybdates are shown to be bifunctional catalysts for epoxidation of alkenes by via oxygen transfer from intermediate alkylhydroperoxides; the latter being formed by catalytic autoxidation with molecular oxygen.

Symmetrical bridgehead-to-bridgehead coupling of bicyclo[1.1.1]pentane cages has been effected in 48−70% yields by the cuprate oxidation method.

Cross-coupling reactions of ( E )- and ( Z )-tosylates of α-hydroxymethylene-γ-butyrolactone with aryl, heteroaryl, alkyl, and alkynylzinc chlorides under Pd(PPh 3 ) 4 catalysis were found to be a suitable synthetic method for stereoselective preparation of α-alkylidene- and substituted alkylidene-γ-lactones. The reactions, conducted under mild conditions, proceed with high stereoselectivity and moderate yields.

The nitrile ylide photochemically generated from 2,3-diphenyl-2H-azirine adds to both isomers of 3-(tosyloxymethylene)tetrahydrofuran-2-one with excellent regio- and stereoselectivity giving spiroheterocyclic products in moderate yields. X-Ray structure determination showed dibutolactone to have the E-configuration. The corresponding Z-isomer was prepared photochemically.