A mild and efficient method using readily available 1-aryl-2,3-allenols and unprotected-N indoles, Au+ -catalyzed cyclization, and aromatization to afford the final [4C+2C] products, carbazoles 4, with an excellent selectivity, is reported. The reaction demonstrates excellent regioselectivity and allows the N-H unit to undergo reactivity unprotected. A mechanism involving a spiropolycyclic intermediate has been proposed and synthetic application is also demonstrated.
Keywords: allenes; aromatization; carbazoles; cyclization; indoles.
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