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Elimination of Benzene from Protonated N-Benzylindoline: Benzyl Cation/Proton Transfer or Direct Proton Transfer?

  • Research Article
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Journal of The American Society for Mass Spectrometry

Abstract

Collision-induced dissociation (CID) of protonated N-benzylindoline and its derivatives was investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS). Elimination of benzene was observed besides hydride transfer and electron transfer reactions. D-labeling experiments and accurate mass determinations of the product ions confirm that the external proton is retained in the fragment ion, and the elimination reaction was proposed to be initiated by benzyl cation transfer rather than proton transfer. Benzyl cation transfer from the nitrogen atom to one of the sp2-hybridized carbon atoms in the indoline core is the key step, and subsequent proton transfer reaction leads to the elimination of benzene. Density functional theory (DFT)-based calculations were performed and the computational results also support the benzyl cation/proton transfer mechanism.

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Acknowledgments

The authors gratefully acknowledge the financial support from the Natural Science Foundation of China (no. 20975092, 21025207) and Natural Science Foundation of Zhejiang Province (Y4100020).

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Authors and Affiliations

  1. Department of Chemistry, Zhejiang University, Hangzhou, China

    Cheng Guo, Lei Yue, Mengzhe Guo & Yuanjiang Pan

  2. Key Laboratory of Organosilicon Chemistry and Material Technology, Hangzhou Normal University, Hangzhou, China

    Kezhi Jiang

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  1. Cheng Guo
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  2. Lei Yue
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  3. Mengzhe Guo
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Correspondence to Yuanjiang Pan.

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Guo, C., Yue, L., Guo, M. et al. Elimination of Benzene from Protonated N-Benzylindoline: Benzyl Cation/Proton Transfer or Direct Proton Transfer?. J. Am. Soc. Mass Spectrom. 24, 381–387 (2013). https://doi.org/10.1007/s13361-012-0561-1

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