Koch-Haaf reverse

Alkyl cations can also be generated by decarbonylation of tertiary acylium ions, like the pivaloyl cation 26 [Eq. (3.20)].91 This reaction corresponds to the reverse of Koch-Haaf acid synthesis, which is known to involve carbocation intermediates. Indeed the reaction of the terf-butyl cation with carbon monoxide gives the pivaloyl cation.91 135... 

Acyl cations are formed in the reversible addition of carbon monoxide to carbonium ions (Balaban and Nenitzescu, 1959 Koch and Haaf, 1958a, b 1961). The formation of the acetyl cation 193 from carbon monoxide and methane in SbF6 has been directly observed by XH n.m.r. 

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See also in sourсe #XX -- [ ]

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