A direct β-coupling of cyclic ketones with imines has been accomplished via the synergistic combination of photoredox catalysis and organocatalysis. Transient β-enaminyl radicals derived from ketones via enamine and oxidative photoredox catalysis readily combine with persistent α-amino radicals in a highly selective hetero radical-radical coupling. This novel pathway to γ-aminoketones is predicated upon the use of DABCO as both a base and an electron transfer agent. This protocol also formally allows for the direct synthesis of β-Mannich products via a chemoselective three-component coupling of aryl aldehydes, amines, and ketones.
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http://dx.doi.org/10.1021/jacs.5b05376 | DOI Listing |
Org Biomol Chem
January 2025
Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, China.
Herein, we report a cascade annulation of readily available isocyanobiaryls with simple aldehydes photoredox catalysis, providing a straightforward approach towards valuable 6-hydroxyalkylated phenanthridines. Mechanistic studies indicated the generation of a key acyl radical from aldehydes by hydrogen atom abstraction with a bromine radical. This protocol exhibits exceptional chemoselectivity, excellent tolerance of various functional groups and mild reaction conditions.
View Article and Find Full Text PDFACS Cent Sci
January 2025
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Multicomponent reactions (MCRs), highly sought-after methods to produce atom-, step-, and energy-economic organic syntheses, have been developed extensively. However, catalytic asymmetric MCRs, especially those involving radical species, remain largely unexplored owing to the difficulty in stereoselectively regulating the extraordinarily high reactivity of open-shell radical species. Herein, we report a conceptually novel catalytic asymmetric three-component radical cascade reaction of readily accessible glycine esters, α-bromo carbonyl compounds and 2-vinylcyclopropyl ketones via synergistic photoredox/Brønsted acid catalysis, in which three sequential C-C (σ/π/σ) bond-forming events occurred through a radical addition/ring-opening/radical-radical coupling protocol, affording an array of valuable enantioenriched unnatural α-amino acid derivatives bearing two contiguous stereogenic centers and an alkene moiety in moderate to good yield with high diastereoselectivity, excellent enantioselectivity and good -dominated geometry under mild reaction conditions.
View Article and Find Full Text PDFOrg Lett
January 2025
School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China.
The catalytic asymmetric multicomponent acylation/rearrangement/cyclization of alkenylfurans with acyl oxime esters/arylamines or acyl oxime esters/arylamines/hydroxylamine has been developed. This method employs synergistic photoredox/Brønsted acid catalysis, enabling the efficient and versatile synthesis of multifunctionalized [3.2.
View Article and Find Full Text PDFMolecules
January 2025
Aix Marseille Univ, CNRS, ICR, 13013 Marseille, France.
In this study we report on the efficiency of a furane-indole-chromenone-based organic derivative () as a photocatalyst in the α-arylation of enol acetate upon LED irradiation at 405 nm, and as a photoinitiator/photocatalyst in the free radical polymerization of an acrylate group in the presence of -(4--butylphenyl)iodonium hexafluorophosphate (Iod) as an additive, or in the presence of both Iod and ethyl-4-(dimethyl amino) benzoate (EDB) under LED irradiation at 365 nm. The photochemical properties of this new light-sensitive compound are described, and the wide redox window (3.27 eV) and the high excited-state potentials / (+2.
View Article and Find Full Text PDFJ Med Chem
January 2025
College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, China.
The hypoxic environment of solid tumors significantly diminishes the therapeutic efficacy of oxygen-dependent photodynamic therapy. Developing efficient photosensitizers that operate photoredox catalysis presents a promising strategy to overcome this challenge. Herein, we report the rational design of two rhenium(I) tricarbonyl complexes ( and ) with electron donor-acceptor-donor configuration.
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