Hypervalent Chalcogenonium⋅⋅⋅π Bonding Catalysis

Abstract

A proof‐of‐concept study of hypervalent chalcogenonium⋅⋅⋅π bonding catalysis was performed. A new catalytic strategy using 1,2‐oxaselenolium salts as chalcogen bond donors and alkenes as chalcogen bond acceptors is described. The feasibility of this concept is demonstrated by the use of trisubstituted selenonium salts in the metal‐free catalytic hydrofunctionalization and polymerization of alkenes via unconventional seleniranium ion‐like intermediates. The results indicate that counter anions have a significant effect on the catalysis based on hypervalent chalcogenonium⋅⋅⋅π bonding interactions.

Electrocatalytic hydrogen evolution mediated by an organotelluroxane macrocycle stabilized through secondary interactions

“…Earth-abundant metals and chalcogenide-stabilized transition compounds have been employed as homogeneous electrocatalysts for hydrogen evolution in nonaqueous solutions. [1][2][3][4][5] Organochalcogen compounds as electrophilic sites have long been known for secondary bonding interactions with electron-rich anion/Lewis bases resulting in applications in the fields of catalysis, [6][7][8][9][10][11][12][13][14] biology, 15 anion transport, [16][17][18][19][20] hostguest chemistry/supramolecular chemistry, [21][22][23][24][25][26][27] and mild oxygen transfer reagents in organic and organometallic synthesis. 28 The chalcogens act as secondary bonding interaction centers, as shown by their VSEPR geometry in oxidation states (II) and (IV), which typically have two positions.…”

“…48,49 1 H,13 C,125 Te,11 B, and19 F NMR spectra were recorded with Bruker AVANCE III 400 and 500 instruments. HRMS data were collected using a Bruker-maXis model (255 552.10138); an ESI-TOF and Q-TOF analyzer was employed to calculate the m/z values.…”

“…The filtrate was concentrated under vacuum, and the white crystalline powder obtained in good yield was separated. CDCl 3 , ppm): δ 7.99 (d), δ 7.04 (d), δ 3.87 (s) 13. C{ 1 H} NMR (125 MHz, CDCl 3 , ppm): δ 162.26, δ 135.44, δ 125.23, δ 115.61, δ 55.57; 19 F NMR (471.6 MHz, CDCl 3 , ppm) δ −109.24, δ −127.07; 11 B NMR (160.77 MHz, CDCl 3 , ppm) δ −0.98; 125 Te NMR (158.22 MHz CDCl 3 , ppm): δ 1148.78 (t, J =…”

Adjusting the balance between hydrogen and chalcogen bonds

“…Of this group of noncovalent bonds, the chalcogen bond (ChB), containing S, Se, or Te, presents a particularly interesting and wide-ranging set of properties and applications. It is prominent in catalysis, [28][29][30][31] for example by activating alkenes, 32 catalysis by sulfonium salts, 33 or as a transfer hydrogenation catalyst. 34 Its function extends to biological systems as for example in enzyme activity of glutathione peroxidase 35 or glutathione peroxidase 35 or as an important element in SAM riboswitches.…”

Pd-Catalyzed Regioselective (Markovnikov) Addition of Aryl Boronic Acids to Terminal Alkynes of 1,3-Dicarbonyl Compounds and Cyclization/Debenzoylation of Olefinic Dicarbonyl: Access to Arylated Pyran and (E)-4-Methylene-1,6-diphenylhex-5-en-1-one

“…Pd-catalyzed reactions of alkynes open new avenues for synthesizing biologically active compounds, natural products, and functional materials . The alkene group is a remarkable functionality that is employed in versatile building blocks in organic synthesis because it is a key structural core that easily participates in wide chemical transformations. , Consequently, the regio- and stereoselective synthesis of aryl-substituted alkene/diene has been a subject of intensive work and attract much attention since it delivers useful precursors for accessing a variety of functionalized and cyclized building blocks . Metal-catalyzed reactions of organoboronic acid have long been the subject of comprehensive research work in organoboron chemistry .…”