Cascade and Effective Syntheses of Functionalized Tellurophenes

Abstract

A one-pot and transition-metal-catalyst-free synthetic strategy to construct functionalized tellurophenes has been developed. Substituted 1,1-dibromo-1-en-3-ynes are smoothly converted to tellurophenes with telluride salts in high yield via a series of cascade reactions through reductive debromination, hydrotelluration, nucleophilic cyclization, and aromatization. Close inspection of the results clearly showed that the reactivity of in situ prepared telluride salts are significantly influenced by the polarity of the solvent system and the electronic nature of the substituent on the enyne substrate. This method reports the first direct synthesis of 3-aryltellurophenes in high yields at room temperature. This novel reaction strategy is also found to be a promising synthetic method for multisubstituted tellurophenes and selenophenes.

Rongalite in PEG-400 as a general and reusable system for the synthesis of 2,5-disubstituted chalcogenophenes

“…Alternatively, cyclization reactions are versatile synthetic strategies to prepare such compounds. For example, they can be synthesized from 1,4-dicarbonyl compounds, 21 1,3-butadiynes, 22 1,3-butadienes, 23 butenes, 24 1,3-enynes 25 and chalcogenoenynes, 26 based on intramolecular cyclizations of chalcogen-containing analogues or reactions with nucleophilic, electrophilic, or radical chalcogen species. 27…”

Quantitative Investigation of Intermolecular Te···A (A = π/Te/H) Interactions in Organotellurium Compounds from the Cambridge Structural Database

“…In bis (1,2,4,5,6-pentahydro-1,3-ditellurapentalen-2-ylidene) ( BIWYOV ), the red dots on the surface indicated close contact distances resulting from Te···Te interactions ( d = 3.583 Å) (Figure (c)), thus suggesting the presence of C–Te···Te interactions. Moving on to 2,4-diphenyltellurophene ( BEYXUB ), the red spots on the surface correspond to C–Te···π ( d = 3.050 Å) and C–H···π interactions, while the white regions indicated Te···Te interactions with a contact distance of 4.124 Å (Figure (d)). In the case of (M)-diphenyl ditelluride ( DPHDTE01 ), the red areas on the d norm surface represented C–Te···π interactions ( d = 3.591 Å), whereas the white color indicated Te···Te contacts ( d = 4.181 Å) (Figure (e)).…”

Visible Light-Induced Difunctionalization of Alkynes: The Synthesis of Thiazoles and 1,1-Dibromo-1-en-3-ynes

“…(4,4-Dibromobut-3-en-1-yne-1,3-diyl)dibenzene (9a). 29 It was obtained as a white solid (77.1 mg, 71%), 1 H NMR (400 MHz, CDCl 3 ): δ 7. 56−7.46 (m, 4H), 7.44−7.32 (m, 6H).…”