Palladium-catalyzed regioselective C-H alkynylation of indoles with haloalkynes: access to functionalized 7-alkynylindoles.

A palladium-catalyzed uniquely regioselective C-H alkynylation of indoles has been described. In this protocol, simple and readily available haloalkynes are employed as efficient alkynylating reagents, affording a series of functionalized 7-alkynylindoles in moderate to good yields. Moreover, further transformations of 7-alkynylated products were performed, which demonstrated the potential application of this method in organic synthesis.