20613-85-8Relevant articles and documents
Combined Experimental and Theoretical Studies on the Radical Nucleophile Addition Reaction for Sulfide- and Selenide-Centered Anions
Bouchet, Lydia M.,Pe?é?ory, Alicia B.,Pierini, Adriana B.,Argüello, Juan E.
, p. 5035 - 5042 (2019/06/17)
The reactivity of sulfur- and selenium-centered nucleophiles toward 1-naphthyl radicals was studied in dimethylsulfoxide. The photostimulated reaction of sulfide anions, -SC(NH)C6H5 (1), -SC(NH)NH2 (2), and -SC(NH)CH3 (3), renders, after the addition of MeI, methyl 1-naphthylsulfide as a main product together with bis(1-naphthyl) sulfide and naphthalene under irradiation. Concordantly, the reaction of selenide anions, -SeC(NH)C6H5 (4), -SeC(NH)NH2 (5), and -SeCN (6), produces methyl 1-naphthyl selenide, bis(1-naphthyl) selenide, and naphthalene in the presence of potassium tert-butoxide anion (entrainment conditions). Absolute rate constants for the coupling of ions 1-6 to 1-naphthyl radicals were determined; as a general trend, the selenide-centered nucleophiles enhance in 2 times the reactivity of their sulfide analogues. From the mechanistic study, it is proposed that the unstable radical anion produced by the addition of the nucleophile to 1-naphthyl radical affords, after fragmentation, 1-naphthylsulfide/selenide anion. In addition, experimental results are discussed in terms of density functional theory calculations. There is a generally good agreement between the experimental and the calculated reactivities, the spin density being the main parameter to describe the difference found among the anions under study. Moreover, the calculations predict that anion -SeC(NH)CH3 (7) would be a good candidate for the synthesis of selenide derivatives.
FeCl3-Diorganyl dichalcogenides promoted cyclization of 2-alkynylanisoles to 3-chalcogen benzo[ b ]furans
Gay, Rafaela M.,Manarin, Flavia,Schneider, Caroline C.,Barancelli, Daniela A.,Costa, Michael D.,Zeni, Gilson
supporting information; experimental part, p. 5701 - 5706 (2010/10/03)
A general synthesis of 3-chalcogen benzo[b]furans from the readily available 2-alkynylanisoles, via FeCl3/diorganyl dichalcogenides intramolecular cyclization, has been developed. Aryl and alkyl groups directly bonded to the chalcogen atom were used as cycling agents. The results revealed that the reaction significantly depends on the electronic effects of substituents in the aromatic ring bonded to the selenium atom of the diselenide species. We observed that the pathway of reaction was not sensitive to the nature of substituents in the aromatic ring of anisole since both the electron-donating and the electron-withdrawing groups delivered the products in similar yields. In addition, the obtained heterocycles were readily transformed to more complex products by using a chalcogen/lithium exchange reaction with n-BuLi followed by trapping of the lithium intermediate with aldehydes, furnishing the desired secondary alcohols in good yields.
