New transition metal-catalyzed methods for the arylation of indolizines by the direct cleavage of C–H bonds have been developed. A wide range of aryltrifluoroborate salts react with indolizines in the presence of Pd(OAc)2 catalyst and AgOAc oxidant to give the arylated indolizines in high yields. Both electron-donating and electron-withdrawing groups perform smoothly while bromide and chlorine substituents are tolerated. In addition, the indolizines display similar reactivities in the Pd-catalyzed reaction with 3-phenylpropiolic acid to afford the corresponding C-3 alkynylated indolizines. These methods allow the direct functionalization of indolizines in one step.
