- Intermolecular [2 + 2] Photocycloaddition of α,β-Unsaturated Sulfones: Catalyst-Free Reaction and Catalytic Variants
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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).
- Jeremias, Noah,Mohr, Lisa-Marie,Bach, Thorsten
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supporting information
p. 5674 - 5678
(2021/08/03)
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- NaOH-promoted thiolysis of oxiranes using 2-[bis(alkylthio)methylene]-3- oxo-N-o-tolylbutanamides as odorless thiol equivalents
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A convenient and efficient protocol for the thiolysis of oxiranes using 2-[bis(alkylthio)methylene]-3-oxo-N-o-tolylbutanamides as thiol equivalents has been developed. Promoted by sodium hydroxide (NaOH) in ethanol at room temperature, the cleavage commences and the generated thiolate anions undergo nucleophilic addition in situ. β-Hydroxy Sulfides were obtained in high yields along with good β-regioselectivity, and trans β-hydroxy Sulfides were also isolated. The thiolysis of one α,β-epoxyketone product with the thiol equivalents was accomplished to afford the corresponding α-carbonyl sulfides in excellent yields. In all the cases, 3-oxo-N-o-tolylbutanamide, the precursor of the thiol equivalents, could be recovered in the novel thiolysis process as a byproduct in good yield. Georg Thieme Verlag Stuttgart.
- Yu, Haifeng,Dong, Dewen,Ouyang, Yan,Wang, Yan,Liu, Qun
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p. 151 - 155
(2008/03/13)
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- 4-hydroxycoumarin derivatives. Part XIII (1). 3-(2'-alkylthioethyl-1'-phenyl)-4-hydroxycoumarins and their oxidation products
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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.
- Sulko, Jerzy
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p. 319 - 324
(2007/10/03)
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- THE CHEMISTRY OF α,ω-MERCAPTOALCOHOLS IN THE PRESENCE OF DIETHOXYTRIPHENYLPHOSPHORANE. TEMEPERATURE DEPENDENCE OF CYCLODEHYDRATIONS AND S-ETHYLATIONS
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Diethoxytriphenylphosphorane (DTPP) is easily prepared by oxidative addition of triphenylphosphine with diethyl peroxide.DTPP converts a variety of mercaptoalcohols to cyclic sulfides as well as hydroxythioethers.The temperature dependence (+25 --> -25 deg C) of the product distribution has synthetic petential.
- Robinson, Philip L.,Kelly, Jeffery W.,Slayton, A. Evans
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