Reported is a tandem palladium-catalyzed Heck/regioselective C(sp3)−H activation reaction for the divergent synthesis of spiro- and fused-cyclopropanated indolines from N-methallylated 2-bromoarylamides. The regioselectivity of the C−H bond activation in the σ-alkylPdII intermediate is controlled by the solvent used. DFT calculations suggest that the polarity of solvent molecules could influence the transition-state energy, leading to a bifurcation of the C−H bond activation in the σ-alkylPdII intermediate.
Bibliographical noteFunding Information:
This work was made possible by the support of the National Research Foundation (NRF-2016R1A2B2013727). D.S.C. acknowledges the Solvay Fellowship. We thank Dr. Y. Kim for X-ray analysis. We also thank Prof. S. Chang at KAIST for use of the time-resolved infrared spectrometer. M.-H.B. acknowledges the financial support from the Institute for Basic Science (IBS-R10-D1).
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- C−H activation
- reaction mechanisms
- solvent effects