Versatile telluracycle synthesis via the sequential electrophilic telluration of C(sp²)–Zn and C(sp²)–H bonds

Abstract

Twofold electrophilic C–Te bond formation has opened access to a wide variety of Te-containing heteroaromatic systems.

Recent advances in selective mono-/dichalcogenation and exclusive dichalcogenation of C(sp2)–H and C(sp3)–H bonds

“…Moreover, the direct C–H tellurination remains largely unexplored compared to the direct C–H thiolation and selenylation, with most of reactions focusing on the C(sp)–H tellurination of terminal alkynes and methyl ketones. 78,80,82–102 The construction of a carbon–tellurium bond is challenging presumably owing to its weak bond strength and metallic nature, resulting in facile metal–tellurium exchange reactions in transition-metal-catalyzed and alkali–metal-mediated reactions. Meanwhile, due to the low electropositive potentials of tellurides, diorgano tellurides are difficult to access under the oxidative conditions used for the synthesis of these compounds.…”

Ring-expansion from tellurophenes to telluropyrans: inhibition of C–Te bond cleavages in transition metal-catalyzed reactions

“…10 Until now, several methodologies have been established for the synthesis of organotellurium compounds. 8,11,20 However, despite these promising advances, the synthetic approaches towards organotellurium molecules fall much behind those for S-and Se-containing compounds since the synthetic methods to build C-S and C-Se bonds always fail to extend the C-Te bond. 12 Moreover, the formed C-Te bond can be easily cleaved by Pt(II), 13 Pd(II), 14 HCl, [15][16][17] LiBu, [18][19][20] and so on (Fig.…”

Simple Access to 2‐Arylbenzo[b]tellurophenes

“…There are several main methodologies for the construction of benzo[ b ]tellurophene's heterocyclic system, including Sashida's [14] electrophilic trapping of tellurium by pregenerated aryllithium species, Takimiya's type [15] nucleophilic substitution of o ‐halogen with in situ generated NaHTe, Rivard's [9] synthesis employing Ph 2 ZrCp 2 and BipyTeCl 2 , and Yoshikai's [16] electrophilic telluration of pregenerated arylzinc [16a] or arylmagnezium [16b] species (Scheme 2). Although all of these protocols provide the desired benzo[ b ]tellurophenes in moderate yields, each of these methods have some downsides.…”