The loss of a methyl radical and the retro diels—Alder reaction in the electron impact mass spectrometry of 2-cyclohexen-1-ol and related compounds

The electron impact mass spectra of 2-cyclohexen-1-ol and of several of its ²H and ¹³C labelled analogues show that the molecular ions lose a methyl radical by a completely different means from the mechanism described previously. Moreover, the retro Diels–Alder reaction also proceeds in a non-classical way; in addition to the elimination of an olefinic molecule from unrearranged molecular ions, a second more important route implies a formal 1,3 allylic rearrangement prior to the retro Diels–Alder reaction. The mass spectra of a series of alkyl substituted homologues show that the competition between the two processes is closely related to the size of the olefinic moiety that is expelled.     

Ruthenium-catalyzed stereospecific decarboxylative allylation of non-stabilized ketone enolates

The ruthenium-catalyzed stereospecific decarboxylative allylation of ketone enolates provides access to gamma,delta-unsaturated ketones with good yields and enantio-enrichments.     

Mössbauer spectroscopic study of the reductive decomposition of iron(III) complexes

Iron injections containing high spin iron(III) complexes may undergo a reductive decomposition during preparation or storage. This process was investigated by the Mössbauer spectroscopy of ice samples prepared by quick-freezing of the injection. The comparison of three model compounds and the correlation between the osmotic pressure of the solutions and their iron(II) concentration formed in the decomposition process and determined by Mössbauer measurements revealed the reason and mechanism of the decomposition.     

1-Fluoro-benzocyclopropenium Ion from 1,1-difluoro-benzocyclopropene

1,1-Difluoro-benzocyclopropene ( 1 ) ionizes in fluorosulphonic acid to yield the cation 2 , which is stable at ? 50° for several hours. Upon quenching with water 2 affords benzoic acid.     

Low-temperature electron radiation damage in scandium

Electron irradiation of hcp scandium at T ? 12 K allowed to determine the energy threshold for Frenkel-pair creation, T_d = 13.8 ± 0.5 eV, and the defect resistivity, $\text{?}{}_{\mathrm{<mtext>F</mtext>}}\text{≈ 5 × 10}{}^{\mathrm{?3}}\text{Ω}\text{cm/F.P}$. The annealing spectrum exhibits four substages between 20 and 70 K, a broad substage centered at 105 K attributed to interstitial long-range migration, and a stage III between 240 and 300 K.