A Scalable Process for the Synthesis of 1,2-Dialkyldiselanes and 1-Alkaneselenols

Abstract

A four-step telescoped process for the synthesis of 1-alkaneselenols entails (1) the rapid formation of potassium selenocyanate from potassium cyanide and selenium in methanol, (2) the nucleophilic substitution of bromoalkanes or alkyl tosylates with potassium selenocyanate, (3) the mild base-catalyzed conversion of the resultant 1-alkaneselenocyanates to 1,2dialkyldiselanes (the Krief reaction), and (4) the reduction of the resultant 1,2-dialkyldiselanes with hypophosphorous acid to give the desired 1-alkaneselenols. The process has been used to produce 1octaneselenol on a 10.4 mol scale. Nine examples of the process are described.

Molecular Main Group Metal Hydrides

“…Alkaneselenols have been known for >70 years with the parent species MeSeH obtained as volatile liquid (bp = 25.5 °C) via the reduction of MeSeSeMe in Na/NH 3 (l) followed by protonation of the selenide generated, Na­[SeMe], with sulfuric acid . In 2019, Blacker and coworkers reported a general high-yield route to various alkaneselenols (up to a kg scale) starting from readily available alkylbromides, as summarized in Scheme . Recently, n BuSeH has been shown to be an effective chain-transfer agent for the chain-transfer polymerization (CTP) of vinylarenes .…”

“…1341 In 2019, Blacker and coworkers reported a general high-yield route to various alkaneselenols (up to a kg scale) starting from readily available alkylbromides, as summarized in Scheme 184. 1342 Recently, n BuSeH has been shown to be an effective chain-transfer agent for the chain-transfer polymerization (CTP) of vinylarenes. 1343 Alkaneselenols have been used as capping ligands for nanoparticles and metal surfaces (akin to the use of thiols as self-assembled monolayers), 1344−1346 1354,1355 and H 2 CCCHSeH (1275) 1356 were prepared and their structures interrogated in the gas phase via microwave spectroscopy.…”

Organic Selenocyanates: Rapid Advancements and Applicationsin the Field of Organic Chemistry

“…[66] A four-step procedures for the synthesis of 1-alkaneselenols 188 and 1,2-dialkydiselanes 187 using alkyl halides or tosylates (186) with KSeCN was revealed by Blacker and coworkers. [67] Intriguingly, the reaction of KSeCN with an alkyl halide or tosylate generates an alkyl selenocyanate intermediate that can progressively produce the corresponding diselanes 187 with good to high yields in the attendance of potassium carbonate (K 2 CO 3 ) in methanol. These diselane compounds 187 can then be reduced in the presence of hypophosphorous acid in 2-propanol to give the targeted alkaneselenols 188 in 91-98% yields (Scheme 87).…”

Synthesis and Applications of Organic Selenols

“…Recently, a four step telescoped process for the synthesis of 1,2‐dialkyldiselenides and 1‐alkaneselenols has also been reported [55] . Simple reactions requiring an easy and fast work‐up were selected in order to address the issues related with the poor stability of selenols and the strong pungent odour of low‐molecular‐weight organoselenium derivatives.…”

“…[54] Recently, a four step telescoped process for the synthesis of 1,2-dialkyldiselenides and 1-alkaneselenols has also been reported. [55] Simple reactions requiring an easy and fast work-up were selected in order to address the issues related with the poor stability of selenols and the strong pungent odour of low-molecular-weight organoselenium derivatives. The optimised stepwise process (Scheme 13) involves the treatment of alkyl halides (or tosylates) with KSeCN, in situ generated from potassium cyanide and elemental selenium.…”