Direct C(sp³)–H Acylation by Mechanistically Controlled Ni/Ir Photoredox Catalysis

Accounts of Chemical Research, Journal Year: 2023, Volume and Issue: 56(16), P. 2170 - 2184

Published: July 28, 2023

ConspectusSynthetic chemists have consistently aimed to develop efficient methods for synthesizing ketones, which are essential building blocks in organic chemistry and play significant roles bioactive molecules. Recent efforts focused on using photoredox catalysis, enables previously inaccessible activation modes, synthesize ketones through the cross-coupling of an acyl electrophile simple C(sp3)-H bonds. Over past few years, we worked developing effective versatile approaches directly acylating activated hydrocarbons forge ketones.Initially, thioesters were explored as source achieve direct acylation ethers, but unexpected thioesterification reaction was observed instead. To gain insights into this reactivity, conducted optimization conditions, substrate scope evaluation, mechanistic studies. Drawing from our understanding Ni/Ir photocatalysis obtained study, subsequently developed a method hydrocarbons. The use less-reactive amides electrophiles found be critical suppressing undesired pathways. This seemingly counterintuitive reactivity carefully studied, revealing substrate-assisted mechanism suppressed oxidative addition leads early-stage nickel oxidation C-H activation.To address drawbacks method, primarily arose decarbonylative transmetallative side pathways, employed N-acyllutidiniums electrophile. prevented decomposition enabling α-chiral substrates with retention their stereochemistry, particularly those derived α-amino acids. methodology allowed us access diverse range homologues.Despite elegant utility Ni/photoredox catalysis new synthetic methodologies, precise behavior catalysts under redox conditions is incompletely understood. insight chemical reactions, used combination experimental computational methods. Our investigations revealed that devised adjustments nickel/photoredox can result differences outcomes, providing opportunities tailor reactions designed strategies. We believe continued study apply modulation will lead discovery additional transformations.

Language: Английский

Titanium in photocatalytic organic transformations: current applications and future developments

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(33), P. 6650 - 6664

Published: Jan. 1, 2024

Titanium, as an important transition metal, has garnered extensive attention in both industry and academia due to its excellent mechanical properties, corrosion resistance, unique reactivity organic synthesis. In the field of photocatalysis, titanium-based compounds such titanium dioxide (TiO

Language: Английский

Origin of site-selectivity of hydrogen atom transfer in carbohydrate C–H alkylations via photoredox catalysis

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(8), P. 2269 - 2276

Published: Jan. 1, 2024

Two major factors, i.e. , C–H σ orbital energy and BDE, account for the HAT site-selectivity of carbohydrates with quinuclidine radical cation.

Language: Английский