Synthesis of carbazoles by dehydro Diels-Alder reactions of ynamides

A new approach to carbazoles and benzannulated carbazoles by means of intramolecular dehydro Diels-Alder of ynamides is reported. N-(o-Ethynyl)aryl ynamides and N-(o-ethynyl) arylynamides were prepared in a few steps starting from o-iodoaniline. Thermal cycloaddition of N-(o-ethynyl)aryl ynamides and N-(o-ethynyl) arylynamides affords carbazoles and benzannulated and heteroannulated carbazoles in moderate-to-good yields.

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