Analytical and Bioanalytical Chemistry

, Volume 377, Issue 7–8, pp 1108–1114 | Cite as

Use of electrospray ionization mass spectrometry for the investigation of radical cation chain reactions in solution: detection of transient radical cations

  • Sven Meyer
  • Jürgen O. MetzgerEmail author
Special Issue Paper


Electrospray ionization mass spectrometry (ESI-MS) coupled to a microreactor is an excellent tool for the investigation of reactions in solution. Here, we report the first results of our investigations into preparatively interesting electron-transfer-initiated chain reactions in solution which proceed via radical cations as reactive intermediates. The tris(p-bromophenyl)aminium hexachloroantimonate (1)-mediated [2+2] cycloaddition of trans-anethole (2) to give 1,2-bis(4-methoxyphenyl)-3,4-dimethylcyclobutane (3) was investigated. The reaction proceeds as a radical cation chain reaction via transient intermediates 2 ●+ and 3 ●+ that could be detected and characterized unambiguously directly in the reacting solution by ESI-MS/MS. The identity of the intermediates was confirmed by comparison with authentic MS/MS spectra of 2 ●+ and 3 ●+ obtained by atmospheric pressure chemical ionization mass spectrometry (APCI-MS). In addition, substrate and product can be monitored easily in the reacting solution by APCI-MS.


Cycloaddition Mass spectrometry Microreactor Radical cation Reactive intermediate 



We thank the German Research Association (DFG) and the Heinz Neumüller Foundation Oldenburg for financial support.


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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  1. 1.Department of ChemistryCarl von Ossietzky UniversityOldenburgGermany

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