176587-07-8Relevant academic research and scientific papers
Competition Between Cα-S and Cα-Cβ Bond Cleavage in β-Hydroxysulfoxides Cation Radicals Generated by Photoinduced Electron Transfer?
Lapi, Andrea,D'Alfonso, Claudio,Del Giacco, Tiziana,Lanzalunga, Osvaldo
, p. 1310 - 1321 (2021/06/07)
A kinetic and product study of the 3-cyano-N-methyl-quinolinium photoinduced monoelectronic oxidation of a series of β-hydroxysulfoxides has been carried out to investigate the competition between Cα-S and Cα-Cβ bond cleavage within the corresponding cation radicals. Laser flash photolysis experiments unequivocally established the formation of sulfoxide cation radicals showing their absorption band (λmax ≈ 520?nm) and that of 3-CN-NMQ? (λmax ≈ 390?nm). Steady-state photolysis experiments suggest that, in contrast to what previously observed for alkyl phenyl sulfoxide cation radicals that exclusively undergo Cα-S bond cleavage, the presence of a β-hydroxy group makes, in some cases, the Cα-Cβ scission competitive. The factors governing this competition seem to depend on the relative stability of the fragments formed from the two bond scissions. Substitution of the β-OH group with -OMe did not dramatically change the reactivity pattern of the cation radicals thus suggesting that the observed favorable effect of the hydroxy group on the Cα-Cβ bond cleavage mainly resides on its capability to stabilize the carbocation formed upon this scission.
Sulfoxide-modified Julia-Lythgoe olefination: Highly stereoselective di-, tri-, and tetrasubstituted double bond formation
Pospisil, Jiri,Pospisil, Tomas,Marko, Istvan E.
, p. 1953 - 1969 (2007/10/03)
A novel modification of the classical Julia-Lythgoe olefination, using sulfoxides instead of sulfones, affords, after in situ benzoylation and SmI 2/HMPA or SmI2/DMPU-mediated reductive elimination, 1,2-di-, tri- and tetrasubstituted olefins in moderate to good yields and E/Z selectivity. The conditions are mild and the procedure is widely applicable. The reaction mechanism was studied and a general model, describing the reaction selectivity, is proposed.
