Methoxymethyl Cations. 3. Reactions of the Gaseous Ions with Acyl Compounds

Article abstract of DOI:10.1021/jo00136a026

Methoxymethyl cations, produced by electron-impact (EI) cleavage of methyl ethers under ICR conditions, were found to react with neutral acyl compounds (AcXR) in various ways.Methyl transfer and loss of formaldehyde from the ion were evident in the reactions with acetamide and N-methyl- and N,N-dimethylacetamide.A competing reaction of wider generality led to ions of composition RX⁺=CH2.The latter reaction also was observed with ethyl, isopropenyl, and allyl acetates, thioacetates, diacetyl sulfide, and N-methyldiacetylimide.A third type of reaction was identifiedas a methoxylation reaction and gave product ions by elimination of CH2=X.A fourth reaction led to ketene elimination and a fifth to 2-methylpropene elimination (R = tert-butyl).These reactions are explained as resulting from the dissociation of a collision complex formed by the attack of the reactant ion at the X atom of the acyl component, AcXR.