239127-26-5Relevant articles and documents
Reaction of singlet oxygen with some benzylic sulfides
Bonesi, Sergio M.,Fagnoni, Maurizio,Monti, Sandra,Albini, Angelo
, p. 10716 - 10723 (2006)
Product distribution, total quenching rate (kT), and rate of chemical reaction (kr) with singlet oxygen have been determined for some alkyl, benzyl, α-methylbenzyl, and cumyl sulfides. Their contributions depend on the steric hindering around the sulfur atom. In protic solvents, the sulfoxide is the main product via a hydrogen-bonded persulfoxide. In apolar solvents, intramolecular α-H abstraction leads to oxidative C-S bond cleavage, with varying efficiency. The behavior of sulfides is compared to that of alkenes and amines.
The photooxygenation of benzyl, heteroarylmethyl, and allyl sulfides
Bonesi, Sergio M.,Torriani, Rosangela,Mella, Mariella,Albini, Angelo
, p. 1723 - 1728 (2007/10/03)
The photosensitised oxidation of benzyl ethyl sulfides in aprotic solvents (benzene or acetonitrile) gives the corresponding aldehydes under mild conditions. This is a general reaction which applies to benzyl derivatives containing either electron-donating or electron-withdrawing substituents and furthermore to hereto analogues such as 2-pyridinylmethyl sulfide (not to the 3-indolylmethyl sulfide, since reaction at the heterocycle moiety competes) as well as to allyl sulfides. In a protic solvent (methanol) these sulfides give the sulfoxides instead (except for the nitrobenzyl derivatives, where the aldehyde remains the major product). Among the α-substituted sulfides tested, the α-phenylbenzyl and the 3- cyclohexenyl sulfide give the corresponding ketone (the latter in a low yield), but the α-methylbenzyl sulfide gives the sulfoxide as the main product. The rate for singlet oxygen quenching and for chemical reaction have been measured for representative benzyl sulfides. The reaction is discussed in the frame of the currently accepted mechanism for sulfide photooxygenation. The key step for oxidative C-S bond cleavage appears to be hydrogen transfer from the activated α position in the first formed intermediate, the persulfoxide. This reaction is inhibited in methanol where the persulfoxide is hydrogen-bonded.
Photosensitized oxygenation of some benzyl sulfides. The role of persulfoxide
Bonesi, Sergio M.,Freccero, Mauro,Albini, Angelo
, p. 703 - 707 (2007/10/03)
Benzyl ethyl sulfide (6a) is photo-oxidized to benzaldehyde in benzene, whereas diethyl sulfide is known to give inefficiently the sulfoxide under these conditions. Oxidative C-S cleavage is the main process also with benzhydryl ethyl sulfide (6c), but not with α-methylbenzyl ethyl sulfide (6b), which mainly gives the sulfoxide. The carbonyl derivatives reasonably arise from S-hydroperoxy ylides (3). Consistently with this finding, calculations at the PM3 level suggest that the first intermediate, the persulfoxide (1), undergoes intramolecular hydrogen transfer when an activated α-hydrogen is available and gives 3. This is the case for the above benzyl sulfides (ΔH* for the process decreases with decreasing C-H BDE). However, only some of the persulfoxide conformations are correctly oriented for this rearrangement, and this may slow this process and make other reactions compete, as happens with 6b. Copyright
