THE INFLUENCE OF THE SUBSTRATE STRUCTURE IN THE TELLUROCYCLOFUNCTIONALIZATION REACTION OF GAMMA,DELTA-UNSATURATED CARBOXYLIC-ACIDS AND THEIR CORRESPONDING BENZYL-ESTERS

gamma,delta-Unsaturated carboxylic acids containing monosubstituted do uble bonds react with aryltellurium trichlorides to give the expected tellurolactone. Reaction of the corresponding benzyl esters gives the addition product of the aryltellurium trichlorides to the double bond. gamma,delta-Unsaturated carboxylic acids containing 1,1-disubstituted double bonds lead to a mixture of the expected tellurolactone and the product of hydrochloric acid addition to the double bond; the corresp onding benzyl ester gives the tellurolactone as the only product. The stereoselectivity of the reaction is low; mixtures of the two possible diastereomeric lactones are formed in approximately 1:1 ratios.