A Lithium Amide Protected Against Protonation in the Gas Phase: Unexpected Effect of LiCl

J Org Chem. 2015 Jun 19;80(12):6441-6. doi: 10.1021/acs.joc.5b00875. Epub 2015 Jun 4.

Abstract

In cold THF and in the presence of LiCl, a lithium pyrrolidinylamide forms a 1:1 mixed aggregate, which is observed directly by ESI-MS. Gas-phase protonation of this species leads to selective transfer of H(+) to the chlorine, suggesting that LiCl shields the amide nitrogen and prevents its direct protonation.