Catalytic, contra-Thermodynamic Positional Alkene Isomerization DOI
Gino Occhialini, Vignesh Palani, Alison E. Wendlandt

et al.

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 144(1), P. 145 - 152

Published: Dec. 30, 2021

The positional isomerization of C═C double bonds is a powerful strategy for the interconversion alkene regioisomers. However, existing methods provide access to thermodynamically more stable isomers from less starting materials. Here, we report discovery dual catalyst system that promotes contra-thermodynamic under photochemical irradiation, providing terminal directly conjugated, internal utility method demonstrated in deconjugation diverse electron-rich/electron-poor alkenes and through strategic application natural product synthesis. Mechanistic studies are consistent with regiospecific bimolecular homolytic substitution (SH2′) mechanism proceeding an allyl-cobaloxime intermediate.

Language: Английский

Energy- and atom-efficient chemical synthesis with endergonic photocatalysis DOI
Huaiju Wang, Ya‐Ming Tian,

Burkhard König

et al.

Nature Reviews Chemistry, Journal Year: 2022, Volume and Issue: 6(10), P. 745 - 755

Published: Sept. 23, 2022

Language: Английский

Citations

60
Contra-Thermodynamic Positional Isomerization of Olefins DOI Creative Commons
Kuo Zhao, Robert R. Knowles

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 144(1), P. 137 - 144

Published: Dec. 30, 2021

A light-driven method for the contra-thermodynamic positional isomerization of olefins is described. In this work, stepwise PCET activation a more substituted and thermodynamically stable olefin substrate mediated by an excited-state oxidant Brønsted base to afford allylic radical that captured Cr(II) cocatalyst furnish allylchromium(III) intermediate. situ protodemetalation allylchromium complex methanol highly regioselective affords isomerized less alkene product. The higher oxidation potential isomer renders it inert further oxidant, enabling accumulate in solution over course reaction. broad range isopropylidene substrates are accommodated, including enol ethers, enamides, styrenes, 1,3-dienes, tetrasubstituted alkyl olefins. Mechanistic investigations step also presented.

Language: Английский

Citations

59
Three-component enantioselective alkenylation of organophosphonates via nickel metallaphotoredox catalysis DOI Creative Commons
Xiaofang Li, Mingbin Yuan, Fan Chen

et al.

Chem, Journal Year: 2022, Volume and Issue: 9(1), P. 154 - 169

Published: Oct. 14, 2022

Language: Английский

Citations

59
High Triplet Energy Iridium(III) Isocyanoborato Complex for Photochemical Upconversion, Photoredox and Energy Transfer Catalysis DOI Creative Commons
Lucius Schmid, Felix Glaser,

Raoul S. Schaer

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(2), P. 963 - 976

Published: Jan. 5, 2022

Cyclometalated Ir(III) complexes are often chosen as catalysts for challenging photoredox and triplet-triplet-energy-transfer (TTET) catalyzed reactions, they of interest upconversion into the ultraviolet spectral range. However, triplet energies commonly employed photosensitizers typically limited to values around 2.5-2.75 eV. Here, we report on a new luminophore, with an unusually high energy near 3.0 eV owing modification previously reported complex isocyanoborato ligands. Compared nonborylated cyanido precursor complex, introduction B(C6F5)3 units in second coordination sphere results substantially improved photophysical properties, particular luminescence quantum yield (0.87) long excited-state lifetime (13.0 μs), addition energy. These favorable properties (including good long-term photostability) facilitate exceptionally organic photoreactions (sensitized) triplet-triplet annihilation fluorescent singlet excited state beyond 4 eV, deep region. The photocatalyzes sigmatropic shift [2 + 2] cycloaddition reactions that unattainable common transition metal-based photosensitizers. In presence sacrificial electron donor, it furthermore is applicable demanding photoreductions, including dehalogenations, detosylations, degradation lignin model substrate. Our study demonstrates how rational ligand design transition-metal underexplored effects) can be used enhance their thereby broaden application potential solar conversion synthetic photochemistry.

Language: Английский

Citations

58
Catalytic, contra-Thermodynamic Positional Alkene Isomerization DOI
Gino Occhialini, Vignesh Palani, Alison E. Wendlandt

et al.

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 144(1), P. 145 - 152

Published: Dec. 30, 2021

The positional isomerization of C═C double bonds is a powerful strategy for the interconversion alkene regioisomers. However, existing methods provide access to thermodynamically more stable isomers from less starting materials. Here, we report discovery dual catalyst system that promotes contra-thermodynamic under photochemical irradiation, providing terminal directly conjugated, internal utility method demonstrated in deconjugation diverse electron-rich/electron-poor alkenes and through strategic application natural product synthesis. Mechanistic studies are consistent with regiospecific bimolecular homolytic substitution (SH2′) mechanism proceeding an allyl-cobaloxime intermediate.

Language: Английский

Citations

58