Synthesis of 1,2-diselenides via potassium persulfate-mediated diselenation of allenamides with diselenides

Abstract

An efficient potassium persulfate mediated radical addition of allenamides with diselenides was developed to create a workable route to 1,2-diselenid products. The reaction tolerates a wide spectrum of functional groups...

Photocatalyst-Free Visible-Light-Promoted C–H Selenylation of Pyrazolo[1,5-a]pyrimidines

“…Significant reduction in the yield of 3a was observed when the reaction of 1a and 2a was performed under optimized reaction conditions in the presence of TEMPO (Scheme 5 ), indicating that the reaction proceeds through a radical pathway. Based on this control experiment and literature reports, 9 12a 13a a probable mechanism of the selenylation is presented in Scheme 5 . It is well known that diselenides absorb visible light and are capable to form phenylselenyl radical both in the presence and absence of photocatalyst.…”

“…9 Initially, the phenylselenyl radical I is formed in the presence of K 2 S 2 O 8 under the irradiation of white LED. 12a 13a Addition of phenylselenyl radical I at C3-position of pyrazolo[1,5- a ]pyrimidine affords the radical intermediate II , which on oxidation affords the cationic intermediate III . Finally, elimination of proton from the intermediate III affords the desired product 3a .…”

Recent advances in the dichalcogenation reactions of unsaturated compounds via double functionalization

“…In 2022, Zhao and coworkers disclosed the synthesis of 1,2-diselenides 44c via K 2 S 2 O 8 -mediated radical diselenation of allenamides 44a with diselenides 44b at room temperature (Scheme 44). 63 The protocol was compatible with a series of N -aryl/alkyl/benzyl and N -2-oxazolidinone-substituted allenamides as well as a variety of diaryl, dibenzyl and dimethyl diselenides. Mechanistically, the K 2 S 2 O 8 -mediated oxidation of the diselenide affords a selenium radical, which selectively adds to the terminal carbon of allenamide to give a relatively stable alkenyl radical 44A .…”

PhI(OAc)2-Mediated Regioselective Hydrothiolation of Allenamides with Thiophenol via a Radical Process: Synthesis of Vinyl Sulfides

“…Nevertheless, developing and expanding more general and efficient strategies for synthesizing vinyl sulfides would still be highly desirable. Based on our previous reports on the intermolecular radical addition reactions of allenamides (Scheme (a)), we here report an efficient PhI­(OAc) 2 -mediated regioselective hydrothiolation of allenamides with thiophenol via a radical process to create a workable route to vinyl sulfides (Scheme (b)).…”