Serendipitous Formation of Various Selenium Heterocycles Hidden in the Classical Synthesis of Selenophene

Abstract

Synthesis of complex di(selenophen-3-yl)diselenides and 3-methylene-3 H -1,2-diselenoles directly from 1-bromobutadiynes is described. The transformation is performed under conditions used before for the synthesis of simple selenophenes from butadiynes. The reaction is operationally straightforward, and complex products were obtained in high yields. Structures of the final products were unambiguously confirmed by the means of 77 Se NMR and single-crystal X-ray diffraction.

Rongalite in PEG-400 as a general and reusable system for the synthesis of 2,5-disubstituted chalcogenophenes

“…To our delight, when 1a was submitted to the dark purple solution (indicative of an in situ Te 2− species) 36 produced by the combination of rongalite, KOH and Te 0 in PEG-400, 4a was obtained in 94% yield at 100 °C (Table 3, entry 9), under the same optimized stoichiometric relationship established for the synthesis of 3a (Table 3, entry 4), and this yield represents a remarkable advance when compared with conventional Te 0 reductive systems available for this kind of transformation. 33 Interestingly, when the reaction temperature was raised to 130 °C (Table 3, entry 10), product 4a was only obtained in 52% yield and the respective starting material 1a was not completely consumed, possibly indicating a thermal instability of the Te 2− species at this reaction temperature. Furthermore, 4a was not detected in the absence of rongalite (Table 3, entry 11).…”

“…Regarding the synthesis of 2,5-disubstituted selenophenes and tellurophenes, only few methodologies have been reported. These are based on the in situ formation of M 2 Y salts (Y = Se, Te) under conventional aqueous/alcoholic reductive systems, 33 or in superbasic media (Y 0 /base/DMSO). 34 However, reaction yields and substrate scopes are usually limited, and additives or catalysts are required in order to increase the efficiency of the reactions.…”

Copper-Catalyzed Cascade Multicomponent Reaction of Azides, Alkynes, and Selenium: Synthesis of Ditriazolyl Diselenides

“…Recently, elemental selenium has received considerable attention as a selenium reagent in constructing organoselenium compounds because of commercial availability, easy handling, low price, and storage stability . The reactions of elemental selenium were also achieved to access diselenides …”

Selenium-Based Drug Development for Antioxidant and Anticancer Activity

“…Selenium-based heterocycles have made a valuable contribution in material science due to their electron-donating and electron-accepting abilities and their ability to modify electronic, structural, and morphological properties [8][9][10][11]. Selenium-based heterocycles have been utilized in small molecules, oligomers, and polymers to improve the electronic properties in an incremental direction [12][13][14][15]. Multiple selenium-containing compounds [12,16] have also been developed to improve the electronic behavior with higher mobility value in field-effect transistor (FET) devices [17].…”