23451-56-1Relevant articles and documents
Intermolecular [2 + 2] Photocycloaddition of α,β-Unsaturated Sulfones: Catalyst-Free Reaction and Catalytic Variants
Jeremias, Noah,Mohr, Lisa-Marie,Bach, Thorsten
supporting information, p. 5674 - 5678 (2021/08/03)
2-Aryl-1-sulfonyl-substituted cyclobutanes were prepared in an intermolecular [2 + 2] photocycloaddition from various α,β-unsaturated sulfones and olefins upon irradiation at λ = 300 nm (26 examples, 60-99% yield). Lewis acids catalyzed the [2 + 2] photocycloaddition of 2-benzimidazolyl styryl sulfones. At short wavelengths, the latter substrates underwent C-S bond cleavage but AlBr3 (5 mol %) allowed for an intermolecular reaction with 2,3-dimethyl-2-butene at longer wavelengths. A chiral-at-metal Lewis acid (2 mol %) facilitated an enantioselective reaction (up to 77% ee).
4-hydroxycoumarin derivatives. Part XIII (1). 3-(2'-alkylthioethyl-1'-phenyl)-4-hydroxycoumarins and their oxidation products
Sulko, Jerzy
, p. 319 - 324 (2007/10/03)
3-(2'-Methylthioethyl-1'-phenyl)-4-hydroxycoumarin and 3-(2'-ethylthioethyl-1'-phenyl)-1-hydroxycoumarin were synthesized. Acetylation of these compounds with acetic anhydride and pyridine yielded respective 4-acetylcoumarins while appropriate sulfoxides and sulfones were obtained by oxidation of alkylthio substituens with H2O2. 3-(2'-ethylthioethyl-1'-phenyl)-4-hydroxycoumarin methylated with diazomethane gave 3-(2'-ethylthioethyl-1'-phenyl)-4-methoxycoumarin and 2-methoxy-3-(2'-ethylthioethyl-1'-phenyl)-chromone.
