Trends in alkyl substituent effects on nucleophilic reactions of carbonyl compounds: Gas phase reactions between ammonia and R1R2COCH3+ oxonium ionsElectronic supplementary information (ESI) available: proton affinities, geometries and energies of optimised structures, structures of the stationary points and a plot of experimental and RRKM ln(kae/ksub) against a-stabilisation constants. See http://www.rsc.org/suppdata/ob/b2/b209955c/
作者:Lihn Bache-Andreassen、Einar Uggerud
DOI:10.1039/b209955c
日期:2003.2.11
The reactivity of carbonyl substituted methyl oxonium ions (R1R2COCH3+) towards ammonia has been investigated using an FT-ICR mass spectrometer and ab initio calculations. The monosubstituted ions (R1 = H; R2 = H, CH3, C2H5 and i-C3H7) show different reaction patterns with variable degree of: (1) nucleophilic substitution, (2) addition-elimination and (3) proton transfer, when reacted with ammonia
The mechanism of formaldehyde loss from the oxonium ions CH<sub>3</sub>CH<sub>2</sub>CH<sub>2</sub>CHO<sup>+</sup>CH<sub>3</sub>and CH<sub>3</sub>CH<sub>2</sub>CH<sub>2</sub>CH<sub>2</sub><sup>+</sup>OCH<sub>2</sub>
作者:Richard D. Bowen、Alex W. Colburn、Peter J. Derrick
DOI:10.1039/c39890001274
日期:——
In contrast to CH3CH2(CH3)CO+CH3 and (CH3)2CHCHO+CH3, which in slow dissociations lose mainly CH3OH, metastable CH3CH2CH2CHO+CH3 exples predominantly CH2O by isomerising to CH3CH2CH2CH2+OCH2, probably via two 1,2-H shifts and a subsequent 1,5-H shift; CH3CH2CH2+OCH2 undergoes limited interconversion with CH3+CHCH2CH2OCH3, prior to CH2O elimination, via a 1,5-H shift.