Sonogashira Cross-Couplings of Ynamides. Syntheses of Urethane- and Sulfonamide-Terminated Conjugated Phenylacetylenic Systems

The first successful Sonogashira coupling of ynamides with aryl and vinyl iodides is described here. This study resolves the problem of the competing pathway involving homocoupling of ynamides and provides a practical entry to novel urethane- or sulfonamide-terminated conjugated acetylenic systems. An interesting tandem hydrohalogenation and Sonogashira coupling was also observed to give an en-ynamide.