Intermolecular versus intramolecular Pauson-Khand reaction in gas phase: Limitation and feasibility

The intermolecular Pauson-Khand reaction has been reproduced in the gas phase by using electrospray ionization coupled to modified tandem mass spectrometry. It has been found, as in solution, that the use of a strained alkene is preferred because of its relatively high reactivity. To observe the final cyclopentenone product, the cobaltacycle produced after a first ion-molecule reaction must necessarily collide with CO. Furthermore, when competition between an inter versus an intra-molecular reaction is possible, the intermolecular reaction is favored. (C) 2016 Elsevier B.V. All rights reserved.