30363-80-5Relevant academic research and scientific papers
The role of hydrogen migration in the mechanism of alcohol elimination from MH+ ions of ethers upon chemical ionization
Morlender-Vais,Mandelbaum
, p. 1124 - 1132 (2007/10/03)
An enhanced elimination of alcohol under isobutane CI conditions, resulting in highly abundant [MH - ROH]+ ions, has been observed in several primary and secondary ethers having a tertiary β-position (methine), as compared with those with β-methylene. This elimination exhibits a significant degree of stereospecificity in stereoisomeric 2-methyl-1-methoxycyclohexanes 4 and 1-methoxy-trans-decalins 7, affording more abundant [MH - ROH]+ ions in the cis isomers 4c and 7tc than in their trans counterparts 4t and 7tt. These findings suggest involvement of a 1,2-hydride migration from the β- to α-position in the course of the alcohol elimination from the MH+ ions of the above cis-ethers, resulting in tertiary carbocation structures. The proposed mechanism of alcohol elimination is supported by a considerable deuterium isotope effect detected in β-deuterium-labeled cis-2-methyl-1-methoxycyclohexane and by a CID study of the structures of [MH - ROH]+ ions obtained from cis- and trans-1,2-dialkoxycyclohexanes. Ring contraction by a Meerwein-type rearrangement has also been observed in the latter system.
Photoinduced Electron Transfer Initiated Activation of Organoselenium Substrates as Carbocation Equivalents: Sequential One-Pot Selenylation and Deselenylation Reaction
Pandey, Ganesh,Soma Sekhar, B. B. V.
, p. 7367 - 7372 (2007/10/02)
The investigation presented in this paper explores the mechanistic aspects and synthetic potentials of PET activation of organoselenium substrates.Fluorescence quenching of 1DCN* by a number of organoselenium compounds (RCH2SeR', 1-4), correlation of the fluorescence quenching rate constants with the oxidation potentials of 1-4, and the dependence of photodissociation quantum yields of 1-4 on their concentration suggests the occurence of electron transfer processes between 1DCN* and 1-4.Steady-state photolysis of 1-4 in the presence of 1DCN* leads to the efficient one-electron oxidative heterolytic dissociation of the carbon-selenium bond to produce the carbocation (RCH2(1+) or equivalent) and radical-centered selenium species (R'Se(.)) via the intermediacy of cation-radical .Nucleophilic assistance in the fragmentation of (RCH2SeR')(1+.) by methanol has been suggested on the basis of products obtained from the control PET reaction of neopentyl phenyl selenide (8).The synthetic utility of these findings has been demonstrated for the deselenylation (Table 4) as well as one-spot sequential selenylation-deselenylation (Table 5) reactions.
