An efficient and practical method for the selective synthesis of sodium diselenide and diorganyl diselenides through selenium reduction

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.…”

“…Notably, the reaction with benzyl bromide (BnBr) provided gradual formation of black solid during the work-up process. It seemed that the generated dibenzyl ditelluride might be decomposed to elemental tellurium, which derives some support from our previous observation [15]. Considering the high stability of analogous dibenzyl diselenide in our previous report [15], this observation seemed surprising.…”

“…It seemed that the generated dibenzyl ditelluride might be decomposed to elemental tellurium, which derives some support from our previous observation [15]. Considering the high stability of analogous dibenzyl diselenide in our previous report [15], this observation seemed surprising. Given this fact, dibenzyl ditelluride could also be unstable while exposed to light and air, which requires further in-depth studies.…”

“…However, there are not enough synthetic studies on organyl tellurium compounds compared to organyl selenium and sulfur compounds. Among many organyl tellurium compounds, dialkyl ditellurides 1 are of our specific interest because we have already performed synthetic studies on diorganyl diselenides (R-Se-Se-R) that are similar to 1 [15]. In our preliminary studies, we found possibilities of selective syntheses of diorganyl ditellurides under mild reaction conditions, and thus focused on selectively synthesizing diorganyl ditellurides.…”

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

“…16,17 Researchers have developed synthetic methods for producing diorganyl diselenides 1 over decades. Compounds 1 were commonly synthesized by the reaction of the diselenide dianion (Se 2 2− ) with alkyl halides, 18–26 and under appropriate conditions, elemental selenium can be reduced to the diselenide dianion using reducing agents like NH 2 NH 2 , 18,20,22,26 NaBH 4 18,24,25 and Li(C 2 H 5 ) 3 BH. 23 In other synthetic methods, compounds 1 were synthesized via the reductive selenation of aldehydes 27 and by the selective oxidative coupling of selenols in the presence of bipyridinium hydrobromide perbromide (BPHP).…”