Publications by authors named "Oliver P Williams"

Herein, we describe a practical protocol for the removal of alcohol functional groups through reductive cleavage of their benzoate ester analogs. This transformation requires a strong single electron transfer (SET) reductant and a means to accelerate slow fragmentation following substrate reduction. To accomplish this, we developed a photocatalytic system that generates a potent reductant from formate salts alongside Brønsted or Lewis acids that promote fragmentation of the reduced intermediate.

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We describe a photocatalytic system that elicits potent photoreductant activity from conventional photocatalysts by leveraging radical anion intermediates generated . The combination of an isophthalonitrile photocatalyst and sodium formate promotes diverse aryl radical coupling reactions from abundant but difficult to reduce aryl chloride substrates. Mechanistic studies reveal two parallel pathways for substrate reduction both enabled by a key terminal reductant byproduct, carbon dioxide radical anion.

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We describe a photocatalytic system that reveals latent photooxidant behavior from one of the most reducing conventional photoredox catalysts, -phenylphenothiazine (). This aerobic photochemical reaction engages difficult to oxidize feedstocks, such as benzene, in C(sp)-N coupling reactions through direct oxidation. Mechanistic studies are consistent with activation of via photooxidation and with Lewis acid cocatalysts scavenging inhibitors inextricably formed in this process.

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Article Synopsis
  • The study presents a novel catalytic method that enhances the efficiency of photocatalysis by electrochemically activating a photocatalyst before using visible light.
  • This new strategy enables the effective use of aryl chlorides in radical coupling reactions, achieving higher reduction potentials than traditional methods like electrolysis.
  • The aryl radicals generated can be utilized for creating carbon-carbon and carbon-heteroatom bonds, showcasing improved reactivity and selectivity compared to existing techniques like photoredox catalysis.
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A palladium-catalyzed multicomponent method for the synthesis of β-lactams from imines, aryl halides, and CO has been developed. This transformation proceeds via two tandem catalytic carbonylation reactions mediated by Pd(PBu) and provides a route to prepare these products from five separate reagents. A diverse range of polysubstituted β-lactams can be generated by systematic variation of the substrates.

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