Tertiary amine self-catalyzed intramolecular C_sp3-H functionalization with in situ generated allenes for the formation of 3-alkenyl indolines

A novel methodology for the synthesis of 3-alkenyl indolines through the reaction of in situ generated allenes with N-benzylic C_sp3-H has been developed. The reaction was realized by Pd(0) catalyzed allenylation of propargyl carbonate with organoboron and subsequent tertiary amine self-catalyzed C_sp3-H functionalization in a one-pot process. Control reactions suggested that the substrate itself might also serve as a Lewis base for the N-benzylic C_sp3-H functionalization.