Attempted hydrogen-deuterium exchange of the protio-trimethyloxonium dication (CH3)3OH2+, study of methylating ability of (CH3)3O+ in superacids and theoretical investigations.
Attempted hydrogen-deuterium exchange of trimethyloxonium ion, (CH3)3O+ with excess of 1:1 (2)HF/SbF5 superacid at -30 degreesC over a period of 30 days showed no exchange. Theoretical calculations at the MP2/6-31G** level are in accord with the lack of hydrogen-deuterium exchange in the methyl group of the (CH3)3O+ cation as protonation (protosolvation) prefers the oxygen lone pair of electrons, instead of a C---H bond. Methylation of aromatics with the (CH3)3O+CF3SO3- in CF3SO3H and 2CF3SO3H:B(O3SCF3)3 was also studied. Whereas in triflic acid no alkylation was observed, in triflatoboric acid, a powerful superacid, alkylation takes place, indicating protolytic activation of the trimethyloxonium ion.
Olah
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GA
Donald P. and Katherine B. Loker Hydrocarbon Research Institute, University of Southern California, University Park, Los Angeles, CA 90089-1661, USA.
Rasul
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Burrichter
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A
Prakash
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GK