EFFICIENT SYNTHESIS OF 2-IODO AND 2-DICYANOMETHYL DERIVATIVES OF THIOPHENE, SELENOPHENE, TELLUROPHENE, AND THIENO[3,2-B]THIOPHENE

An effective synthesis of 2-iodothiophene, 2-iodotellurophene, and 2-i odothieno[3,2-b]thiophene and a Pd-catalyzed carbon-carbon coupling re action of these iodo derivatives as well as 2-iodoselenophene with mal ononitrile affording novel thienyl-, tellurienyl-, thieno[3,2-b]thieny l-, and selenienylmalononitrile are described. These heteroarylmalonon itriles are important synthons for the preparation of 2-dicyanomethyle ne-2,5-dihydroheterophene chromophores.