title: Why does pivalaldehyde (trimethylacetaldehyde) unexpectedly seem more basic than 1-adamantanecarbaldehyde in the gas phase? FT-ICR and high-level ab initio studies.
abstract: Fourier transform ion cyclotron resonance spectroscopy (FT ICR) techniques, including collision-induced dissociation (CID) methodology, were applied to the study of the gas-phase protonation of pivalaldehyde (1) and 1-adamantanecarbaldehyde (2). A new synthetic method for 2 was developed. The experiments, together with a thorough computational study involving ab initio and density functional theory (DFT) calculations of high level, conclusively show that upon monoprotonation in the gas phase, compound 1 yields monoprotonated methyl isopropyl ketone 3. The mechanism of this gas-phase acid-catalyzed isomerization is different from that reported by Olah and Suryah Prakash for the reaction in solution. In the latter case, isomerization takes place through the diprotonation of 1.
authors.affiliation: Instituto de Química Física Rocasolano, CSIC, C/Serrano 119, 28006 Madrid, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Quintanilla
authors.forename: Juan Z
authors.initials: JZ
authors.lastname: Dávalos
authors.forename: José-Luis M
authors.initials: JL
authors.lastname: Abboud
authors.forename: Manuel
authors.initials: M
authors.lastname: Alcamí
authors.forename: M Pilar
authors.initials: MP
authors.lastname: Cabildo
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Claramunt
authors.forename: José
authors.initials: J
authors.lastname: Elguero
authors.forename: Otilia
authors.initials: O
authors.lastname: Mó
authors.forename: Manuel
authors.initials: M
authors.lastname: Yáñez