The structure and mechanism of formation of C5H9O+from ionized phytyl methyl ether

✍ Scribed by R.D. Bowen; R.T. Gallagher; S. Meyerson

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 350 KB
• Volume: 7
• Category: Article
• ISSN: 1044-0305
• DOI: 10.1016/1044-0305(95)00679-6

✦ Synopsis

The recent proposal that ionized phytyl methyl ether [C,,H,,(CH,)C =CHCH,OCHl'] undergoes an allylic rearrangement to ionized isophytyl methyl ether [CH, = CHC(C,,H,,XCH,)OCH,f'] before elimination of an alkyl radical is discussed. Both literature precedent and new results in which the structure of the [M -C,,Hj.J+ fragment ion is established by comparison of its collision-induced dissociation mass spectrum with the spectra of isomeric C,H,O+ ions of known structure are inconsistent with this proposal. The formation of CH,CH=CHCH

=O+CHa by loss of a y-alkyl substituent without skeletal isomerization rather than CH, = CHCfCH,) = O+CH, after allylic rearrangement is explained in terms of a mechanism that involves two 1,2-H shifts, followed by a-cleavage of the resultant ionized enol ether, C,,H,,(CH,)CH-CH =CHOCHz' .