Recent Advances in Organochalcogen Synthesis Based on Reactions of Chalcogen Halides with Alkynes and Alkenes

Потапов, В. А.; Мусалов, М. В.; Мусалова, М. В.; Амосова, С. В.

doi:10.2174/1385272819666150810222454

Cited by 75 publications

(45 citation statements)

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“…), the product 2 a was obtained in 59% yield after 2 h, at room temperature (Table 1, entry 6). Control experiments indicated that the solvents directly influenced the yields of 2 a, whereas the best yield was obtained by using THF as the solvent (Table 1, entries [10][11][12][13][14][15][16][17][18][19]. ; however, the yields decreased with 1.0 equiv.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of 3‐Substituted Chalcogenophene‐Fused Indoles from 2‐Alkynylindoles

2019

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The intramolecular electrophilic cyclization of 3-organoselanyl-2-alkynylindoles providing the synthesis of 3-iodo-selenophene-fused indoles is reported herein. The strategy was extended to the preparation of 3-iodo-thiophene-fused indoles in a one-pot iodine-promoted thiolation of 2-alkynylindoles, followed by an electrophilic cyclization sequence. Besides, the synthesis of 3-butylselanyl-selenophene-fused indoles from 3butylselanyl-2-alkynylindoles was also developed using iron(III) chloride and dibutyl diselenide to promote the cyclization and functionalization of the heterocycle. The identification of the alkyl halide intermediate afforded evidence to the proposed mechanism, which indicated that the reactions proceed through the formation of an iodonium ion, followed by a selenium 5-endo-dig cyclization, to afford the indole derivatives. The 3-iodo-selenonophene-fused indoles prepared were applied as substrates in copper-catalyzed crosscoupling reactions with thiols to give the Ullmann type products in good yields. Scheme 2. General strategy for the preparation of 3-organoselanyl-2-alkynylindoles. Scheme 3. 3-Organoselanyl-2-alkynylindoles prepared.

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Section: Resultsmentioning

confidence: 99%

Synthesis of 3‐Substituted Chalcogenophene‐Fused Indoles from 2‐Alkynylindoles

2019

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“…An early example of this behaviour is the formation of base-stabilised SCl2•tmtu from treatment of SeCl4 with tetramethylthiourea (tmtu) [10]. More, recently, it has been shown that thioether ligands also Although reactions of selenium tetrahalides with alkenes and alkynes have been studied extensively in early work, recent attention has been focused on the applications of selenium dihalides for the synthesis of organoselenium compounds (see Section 2.3) [13].…”

Section: 3)mentioning

confidence: 99%

2. Selenium– and tellurium–halogen reagents

Chivers¹,

Laitinen²

2019

Selenium and Tellurium Reagents

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Selenium and tellurium form binary halides in which the chalcogen can be in formal oxidation states (IV), (II) or (I). They are versatile reagents for the preparation of a wide range of inorganic and organic selenium and tellurium compounds taking advantage of the reactivity of the chalcogenhalogen bond. With the exception of the tetrafluorides, the tetrahalides are either commercially available or readily prepared. On the other hand, the low-valent species, EX2 (E = Se, Te; X = Cl, Br) and E2X2 (E = Se, Te; X = Cl, Br) are unstable with respect to disproportionation and must be used as in situ reagents. Organoselenium and tellurium halides are well-known in oxidation states (IV) and (II), as exemplified by REX3, R2EX2, and REX (R = alkyl, aryl; E = Se, Te; X = F, Cl, Br, I), as well as mixed-valent (IV/II) compounds of the type RTeX2TeR are also known. This chapter surveys the availability and/or preparative methods for these widely used reagents followed by examples of their applications in synthetic inorganic and organic selenium and tellurium chemistry. For both the binary halides and their organic derivatives the discussion is subdivided according to the formal oxidation state of the chalcogen.

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“…The selenium-containing heterocyclic drug ebselen is applied for the prevention and treatment of human ischemic stroke [21]. The development of effective approaches to novel selenium heterocycles by regioselective cyclization and annulation reactions is one of the main directions of our research [22][23][24][25][26][27][28][29][30][31]. The reactions of 2-pyridinesulfenyl and 2-pyridineselenenyl chlorides with some alkenes have been described [32][33][34][35][36][37][38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

Natural Compounds and Their Structural Analogs in Regio- and Stereoselective Synthesis of New Families of Water-Soluble 2H,3H-[1,3]thia- and -Selenazolo[3,2-a]pyridin-4-ium Heterocycles by Annulation Reactions

et al. 2020

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It has been found that both eugenol and isoeugenol derivatives reacted with 2-pyridinesulfenyl and 2-pyridineselenenyl halides in a regioselective mode affording products with opposite regiochemistry. Synthesis of new families of 2H,3H-[1,3]thia- and -selenazolo[3,2-a]pyridin-4-ium heterocycles has been developed by annulation reactions of 2-pyridinechalcogenyl halides with natural compounds (eugenol, isoeugenol, methyl eugenol, methyl isoeugenol, acetyl eugenol, trans-anethole) and their structural analogs. The influence of the substrate structure and the nature of halogen on the product yields are studied. The 2-pyridinesulfenyl and 2-pyridineselenenyl chlorides are more efficient reagents compared to corresponding bromides. The obtained condensed heterocycles are novel water-soluble functionalized compounds with promising biological activity.

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Recent Advances in Organochalcogen Synthesis Based on Reactions of Chalcogen Halides with Alkynes and Alkenes

Cited by 75 publications

References 0 publications

Synthesis of 3‐Substituted Chalcogenophene‐Fused Indoles from 2‐Alkynylindoles

Synthesis of 3‐Substituted Chalcogenophene‐Fused Indoles from 2‐Alkynylindoles

2. Selenium– and tellurium–halogen reagents

Natural Compounds and Their Structural Analogs in Regio- and Stereoselective Synthesis of New Families of Water-Soluble 2H,3H-[1,3]thia- and -Selenazolo[3,2-a]pyridin-4-ium Heterocycles by Annulation Reactions

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