An Efficient Method for Selective Syntheses of Sodium Selenide and Dialkyl Selenides

Abstract

The studies on the selective synthesis of dialkyl selenide compounds 1 were presented. Overcoming the complexity and difficulty of selenides (R-Se-R) and/or multiselenides (R-Sen-R; n ≥ 2), we aimed to optimize the reaction condition for the tolerable preparation of sodium selenide (Na2Se) by reducing Se with NaBH4, and then to achieve selective syntheses of dialkyl selenides 1 by subsequently treating the obtained sodium selenide with alkyl halides (RX). Consequently, various dialkyl selenides 1 were efficiently synthesized in good-to-moderate yields. The investigations on reaction pathways and solvent studies were also described.

Studies on the Selective Syntheses of Sodium Ditelluride and Dialkyl Ditellurides

“…Although the crude product 1a was obtained in reasonable yields in most of the reactions, the ratios of ditelluride 1a to telluride 2a were fluctuated depending on the reaction conditions (Table 1), which is consistent with our previous observations [15,25]. When NaBH 4 was used in the range of 0.8-1.5 eq, the yields increased with the increasing amount of NaBH 4 , but the ratios of 1a to 2a decreased.…”

Synthesis and structural properties of para-diselenopyrazines

“…Since selenium nucleophiles are highly sensitive towards oxidation and thus unstable, for the incorporation of selenium into the pyrazine core it was necessary to generate an active nucleophilic selenium species in situ . 20 While numerous reports describe the formation of sodium selenide using NaBH 4 , 21,22 we achieved the best outcomes using LiBEt 3 H, which has also been reported as a highly effective reductant in earlier publications. 23 For this kind of nucleophilic cyclizations, it is typically necessary to use high boiling aprotic polar solvents such as dimethylformamide 24 or N -methyl-2-pyrrolidone, 25 which are difficult to remove in the subsequent workup protocol.…”

Studies on the selective synthesis of diorganyl diselenides using potassium hydroxide and mechanistic investigations of the reaction pathway

“…31,32 However, some of the synthetic methods often resulted in the production of unwanted side products, diorganyl selenides 2 (R–Se–R) or multiselenides (R–Se n –R) that are difficult to remove from the desired products 1 (R–Se–Se–R). 19,21,33 On the other hand, other methods require harsh reaction conditions or the use of highly reactive or toxic reagents. In addition, we have experienced discrepancies with the reported results and encountered difficulties in reproducing them, which we attributed to the sensitivity of selenium compounds to redox conditions.…”