Studies On The Reductive Selenation And Catalyzed Hydrogenation Using Se/CO/H₂O System Under Atmospheric Pressure

In the paper, we researched a kind of reactions using Se/CO/H₂O/DMFsystem to reduce selenation of aldehydes, ketones, alkyl halides and nitriles andcatalyzed hydrogenation of a,β-unsaturated carbonyl compounds underatmospheric pressure in mild conditions.An efficient and new method for the synthesis of symmetrical dibenzyldiselenides is described. Reductive selenation of aromatic and heterocyclicaromatic aldehydes with stoichiometric selenium in CO/H₂O system in DMFafforded symmetrical diselenides in yields up to 94% under atmospheric pressurein mild conditions without use of a base. The advantages of the present methodare simple manipulation, easily available product, mild and neutral conditions.What's more, we expanded the reaction to aliphatic ketones and aldehydes undersimilar conditions and found that these reactions led to dialkyl diselenides underatmospheric pressure in the absence of base in from moderate to good yields.On the basis, we investigated the reaction of selective reduction ofa,β-unsaturated carbonyl compounds and found that under atmospheric pressurethe Se(cat.)/CO/H₂O/DMF system was successfully usable for the selectivereduction of a,β-unsaturated carbonyl compounds in the absence of base in highyields up to 99%. The novel method is not only reducing the reaction condition,realizing the selenium-catalyzed reaction, but also reducing the reaction times.In addition, we used active alkyl halides and nitriles as starting materials, withstoichiometric selenium in CO/H2O system, in the presence of inorganic basesodium hydroxide or without use of a base, in DMF under atmospheric pressure togive symmetrical diselenides and selenocarboxamides. In summary, we reported a new method which enriched the application ofSe/CO/H₂O system. We think the paper will benefit both the academic andindustrial societies who deal with organoselenium chemistry.