60126-98-9Relevant articles and documents
Unimolecular Dissociations of the +. Metastable Ion
Bouchoux, Guy,Tortajada, Jeanine,Dagaut, Jacques,Fillaux, Joelle
, p. 451 - 457 (1987)
The metastable molecular ion of 2-hexanone loses a methyl radical mainly (ca. 80percent) from positions C(4) and C(6), in equal proportions, as indicated by 13C labelling.The necessary skeletal rearrangement of the butyl chain is interpreted in terms of a 1,2-+. shift .The results and the mechanisms concerning the minor eliminations of C2H4, C2H5., C3H5. and C3H6 neutrals are also discussed.
Stereochemical preferences in 4-center Syn-eliminations from gaseous ions
Cao, Tangyuan,Nguyen, Michael K.,Serafin, Scott V.,Morton, Thomas Hellman
, p. 6099 - 6107 (2008/12/22)
(Chemical Equation Presented) Concerted unimolecular eliminations from ionized sec-alkyl aryl ethers (ROAr+?) display a preference for producing double bonds with trans geometry. This preference can be assessed quantitatively, provided that a regioselective variant can be found. Expulsion of neutral alkenes via .syn-elimination to give ionized ArOH does not exhibit a pronounced preference with regard to the direction of elimination. By contrast, ionized 2-hexyl p-trifluoromethylphenyl ether eliminates neutral ArOH regioselectively, giving ionized 2-hexenes rather than ionized 1-hexene. Vicinally monodeuterated 2-hexyl and 3-hexyl ethers were prepared as pure diastereomers. Metastable ion decompositions of their gaseous radical cations are compared over two different time windows. The regioselectivity for the 2-hexyl ether allows the geometric preference for the double bonds to be estimated based on the difference between the erythro and threo monodeuterated diastereomers (trans/cis = 2.0 for producing ionized 2-hexene from parent ions with the lowest internal energies). The 3-hexyl ethers and ionized 2- and 3-phenoxyoctanes also undergo stereoselective elimination but give experimental values that reflect their lack of regioselectivity. Examination of erythro/threo combinations shows that GC/MS/MS has the ability to quantitate stereochemistry in mixtures containing both positional and stereoisomers.