Metal free C-3 chalcogenation (sulfenylation and selenylation) of 4<i>H</i>-pyrido[1,2-<i>a</i>]pyrimidin-4-ones

Ghosh, Prasanjit; Chhetri, Gautam; Das, Sajal

doi:10.1039/d1ra00834j

Cited by 16 publications

(11 citation statements)

References 60 publications

(25 reference statements)

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“…Methods for pyridopyrimidin-4-ones selenylation with diselenides were also developed. For this purpose, I 2 /K 2 S 2 O 8 system [215] and PIFA [216] are applied. Various aromatic and aliphatic diselenides efficiently react with pyridopyrimidin-4-ones, containing electron-donating Quinazolinones 191 are sulfenylated with disulfides 192 with the use of Cu(OAc) 2 and p-benzoquinone (Scheme 83).…”

Section: Reactions With the Formation Of Cà S And Cà Se Bondsmentioning

confidence: 99%

CH‐Functionalization of Heterocycles with the Formation of C−O, C−N, C−S/Se, and C−P Bonds by Intermolecular Addition of Heteroatom‐Centered Radicals

et al. 2023

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In the last decade, free radicals have found a wide application in functionalization of unsaturated compounds, such as alkenes, alkynes, and arenes, via the free-radical addition to carbon-carbon π-bonds. In these processes, intermolecular free-radical attack on the aromatic substrates represents a challenge due to relatively high resistance of aromatic π-system to addition reactions in comparison to alkene C=C bonds. The free-radical functionalization of heterocycles is especially interesting due to the diversity of their structures and chemical properties as well as their importance for medicinal chemistry, agrochemistry, and materials science. Addition of C-centered radicals to heterocycles is widely known as the Minisci-type reactions and well-reviewed. In this paper, we have summarized the main achievements in less explored group of processes: functionalization of heterocycles by intermolecular addition of heteroatom-centered radicals (O-, N-, S-/Se-, and P-radicals) with the emphasis on the papers published after 2010. Literature analysis revealed the strong trend towards the usage of electrochemistry and photoredox-catal-ysis for the generation of free radicals in recent years. The remaining fundamental problem in this field is the lack of strong experimental support for the proposed mechanisms and frequent existence of several plausible reaction pathways. The progress in mechanistic studies can significantly improve the prediction of optimal reaction conditions depending on the substrates structure. 1. Introduction 2. Radical Functionalization of Heterocycles 2.1. Reactions with the Formation of CÀ O Bonds 2.2. Reactions with the Formation of CÀ N Bonds 2.3. Reactions with the Formation of CÀ S and CÀ Se Bonds 2.4. Reactions with the Formation of CÀ P Bonds 3. Conclusions

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Section: Reactions With the Formation Of Cà S And Cà Se Bondsmentioning

confidence: 99%

CH‐Functionalization of Heterocycles with the Formation of C−O, C−N, C−S/Se, and C−P Bonds by Intermolecular Addition of Heteroatom‐Centered Radicals

et al. 2023

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“…was also consumed. At the same time, they found that excellent yields could be also obtained by using iodine molecule (I 2 ) instead of hypervalent iodine reagent (PIFA) (Scheme 2, c), [13] however, excessive oxidant (K 2 S 2 O 8 ) consumption remains another problem. Although C 3 ‐selenylated 4H‐pyrido[1,2‐ a ]pyrimidin‐4‐ones were synthesized in moderate to good yields via above selenation reaction, these methods all require excessive consumption of diphenyldiselenide and use a lot of iodine reagents or oxidants, which do not meet the requirements of atom‐economy.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Oxidative Selenation of 4H‐Pyrido‐[1,2‐a]‐pyrimidin‐4‐ones with Diorganyldiselenides

et al. 2023

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An environmentally friendly protocol for the synthesis of C3‐selenylated 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones was developed via the electrochemical oxidation, iodide‐catalyzed selenation of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones with diaryl (alkyl) diselenides under oxidant‐ and external electrolyte‐free conditions. Only by using 10 mol % of KI as catalyst and electrolyte, the selenation can proceed efficiently, and give corresponding products in good to excellent yields, avoiding the use of excess oxidant or iodinated reagents.

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“…The cross-coupling reaction of halogenated or boronated alkenes and selenium reagents, e.g., ArSeSeAr and KSeCN, offers another alternative, which primarily affords the disubstituted selenium-containing olefins. In recent years, C(sp 2 )–H bond selenization has provided another method for obtaining selenoethylene . However, the stereoselective synthesis of acyclic tetrasubstituted vinyl selenides is still challenging (Scheme b).…”

mentioning

confidence: 99%

Highly Stereoselective Synthesis of Tetrasubstituted Vinyl Selenides via Rhodium-Catalyzed [1,4]-Acyl Migration of Selenoesters and Diazo Compounds

Liu

Dong

et al. 2022

Org. Lett.

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Metal free C-3 chalcogenation (sulfenylation and selenylation) of 4H-pyrido[1,2-a]pyrimidin-4-ones

Abstract: We have discovered an unprecedented metal-free route for the direct C-3 chalcogenation of various 4H-pyrido[1,2-a]pyrimidin-4-ones under mild conditions in good to excellent yields.

Cited by 16 publications

References 60 publications

CH‐Functionalization of Heterocycles with the Formation of C−O, C−N, C−S/Se, and C−P Bonds by Intermolecular Addition of Heteroatom‐Centered Radicals

CH‐Functionalization of Heterocycles with the Formation of C−O, C−N, C−S/Se, and C−P Bonds by Intermolecular Addition of Heteroatom‐Centered Radicals

Electrochemical Oxidative Selenation of 4H‐Pyrido‐[1,2‐a]‐pyrimidin‐4‐ones with Diorganyldiselenides

Highly Stereoselective Synthesis of Tetrasubstituted Vinyl Selenides via Rhodium-Catalyzed [1,4]-Acyl Migration of Selenoesters and Diazo Compounds

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