CH2+transfer to pyridine nucleophiles: a means of producing α-distonic ions

✍ Scribed by Sophia J. Yu; Michael L. Gross; Kenneth R. Fountain

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 793 KB
• Volume: 4
• Category: Article
• ISSN: 1044-0305
• DOI: 10.1016/1044-0305(93)85067-8

✦ Synopsis

The distonic radical cation C5H5N(+)-(·)CH2 can be generated by the reactions of neutral pyridine with the radical cations of cyclopropane, ethylene oxide, and ketene, as well as with the C3H6 ion from fragmentation of tetrahydrofuran. The distonic product ion can be distinguished from isomeric methylpyridine radical cations because the former gives characteristic M-CH2, M - CH2NCH, and a doubly charged ion, all of which are produced on collisional activation. Furthermore, the distonic species completely transfers CH2 (+) to more nucleophilic, substituted pyridines. These properties are all consistent with the assigned distonic structure. Another distonic isomer, the (3-methylene) pyridinium ion, can be distinguished from the (1-methylene)pyridinium ion on the basis of their different fragmentation behaviors. The latter ion exhibits higher stability (lower reactivity) than the prototypal [·CH2NH3 (+)], making available a distonic species whose bimolecular reactivity can be readily investigated.