A simple and expedient approach for the synthesis of functionalized 2-aminoquinolines via palladium-catalyzed annulation of N-acyl-o-alkynylanilines with isocyanides has been developed with high atom economy, in which an unconventional 6-endo-dig cyclization process is observed. Further investigations of the mechanism demonstrated that an intramolecular acyl migration of the N-protecting groups was involved in this transformation.

A straightforward approach for the assembly of different polysubstituted propiolamidnates via palladium-catalyzed multicomponent reaction of isocyanides, haloalkynes, and amines has been reported in which the C­(sp)–C­(sp2) and C­(sp2)N bonds were constructed in one pot. This reaction featured in high efficiency, excellent chemoselectivity, and good functional group compatibility. The synthetic utility of this method was also demonstrated.

A palladium-catalyzed exclusively selective alkynylation of indoles has been reported, affording concise access to 7-alkynylindoles from readily available starting materials.

A novel and efficient palladium-catalyzed annulation of anilines with bromoalkynes for the synthesis of 2-phenylindoles has been described. This approach features excellent regio-and stereoselectivities and good functional group tolerance. Preliminary mechanistic studies indicate that anilines undergo anti-nucleophilic addition to bromoalkynes to generate (Z)-N-(2-bromo-1-phenylvinyl) anilines, followed by sequential C−H functionalization to deliver different substituted 2-phenylindoles. This method provides potential applications for the construction of various biologically active compounds.

An efficient, palladium(II)-catalyzed, C(sp 2 )-H alkynylation/annulation of 2-phenylphenols with haloalkynes for the synthesis of substituted 6-methylene-6H-dibenzo [b,d]pyrans is reported. This protocol features a traceless directing group strategy, unique regioselectivity and mild reaction conditions. Significantly, preliminary mechanistic studies suggest that the sequential C(sp 2 )-H alkynylation and annulation reaction could be involved in the transformation procedure.