Electron-impact study of norbornane derivatives

Synthesis and Stereochemical Properties of Chiral Square Complexes of Iron(II)

“…1). The conclusions derived from this study, in combination with earlier studies reported on the EI behavior of other norbornane derivatives,6–16 constitute an interesting contribution to facilitating the mass spectral characterization of this valuable class of chiral molecules for which no systematic mass spectral studies have been carried out due to the lack of general synthetic procedures for their preparation.…”

“…Depending on the structural nature and electronic properties of the bridgehead substituent, the charge in the molecular ion can be preferentially located at the ketonic carbonyl oxygen, or on the heteroatomic substituent. Accordingly, as shown in Scheme , the molecular ion of 1a – p can undergo competitive homo‐ or heterolytic C(1)–C(2) and C(2)–C(3) bond cleavages as occurs in the case of camphor,9–12 although the subsequent fragmentation processes are quite different. The C(2)–C(3) bond cleavage can be radical‐ or charge‐driven leading to isomeric radical cations in which the positions of the unpaired electron and the charge are reversed.…”

“…Heterolytic inductive cleavage of C(2)–C(3) bond, whose driving force is the stabilization of the charge at the quaternary center C(3), gives rise to the distonic radical cation 2 in which the charge is located at C(3) and the unpaired electron at the acyl group. Inductive cleavage becomes an important process, even more than α‐cleavage, in bicyclic ketones such as camphor9–12 and strained steroidal ketones18 as a consequence of stabilization of the charge by formation of a tertiary carbocation. Homolytic C(2)–C(3) bond cleavage leads to iso ‐ 2 in which the charge is located at the acyl group and the unpaired electron at C(3).…”

Odor Characterization of the Synthetic Stereoisomers of 2-Methylborneol

“…The crude product weighed 2 g. This product was analyzed by GC/MS. At a constant column temperature of 150 "C, a peak eluted in 2.7 min, with a mass spectrum which had a significant abundance at mass 150, the molecular weight of 2-methylenebornane, and showed a base peak of 107 which is typical of many borneol compounds (Dimmel and Wolinsky, 1967). This compound constituted 22% of the total product as determined by relative peak height measurement.…”

Essential Oil ofChrysanthemum indicum

“…[m/z 137 -CU], in both spectra). The base peak at m/z 81 in the El spectrum could be compatible with a 4-methyl-bicyclo-[2,2,1]-heptane skeleton[13].…”