Fischer Indole Synthesis in the Gas Phase, the Solution Phase, and at the Electrospray Droplet Interface

Ryan M Bain; Stephen T Ayrton; R Graham Cooks

doi:10.1007/s13361-017-1597-z

Fischer Indole Synthesis in the Gas Phase, the Solution Phase, and at the Electrospray Droplet Interface

J Am Soc Mass Spectrom. 2017 Jul;28(7):1359-1364. doi: 10.1007/s13361-017-1597-z. Epub 2017 Feb 13.

Authors

Ryan M Bain¹, Stephen T Ayrton¹, R Graham Cooks²

Affiliations

¹ 560 Oval Drive Department of Chemistry and the Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, USA.
² 560 Oval Drive Department of Chemistry and the Center for Analytical Instrumentation Development, Purdue University, West Lafayette, IN, 47907, USA. cooks@purdue.edu.

PMID: 28194736
DOI: 10.1007/s13361-017-1597-z

Abstract

Previous reports have shown that reactions occurring in the microdroplets formed during electrospray ionization can, under the right conditions, exhibit significantly greater rates than the corresponding bulk solution-phase reactions. The observed acceleration under electrospray ionization could result from a solution-phase, a gas-phase, or an interfacial reaction. This study shows that a gas-phase ion/molecule (or ion/ion) reaction is not responsible for the observed rate enhancement in the particular case of the Fischer indole synthesis. The results show that the accelerated reaction proceeds in the microdroplets, and evidence is provided that an interfacial process is involved. Graphical Abstract .

Keywords: Accelerated reactions; Electrospray; Fischer indole synthesis.