A General Approach to Intermolecular Olefin Hydroacylation through Light‐Induced HAT Initiation: An Efficient Synthesis of Long‐Chain Aliphatic Ketones and Functionalized Fatty Acids

Abstract

Herein, an operationally simple, environmentally benign and effective method for intermolecular radical hydroacylation of unactivated substrates by employing photo‐induced hydrogen atom transfer (HAT) initiation is described. The use of commercially available and inexpensive photoinitiators (Ph2CO and NHPI) makes the process attractive. The olefin hydroacylation protocol applies to a wide array of substrates bearing numerous functional groups and many complex structural units. The reaction proves to be scalable (up to 5 g). Different functionalized fatty acids, petrochemicals and naturally occurring alkanes can be synthesized with this protocol. A radical chain mechanism is implicated in the process.

Decatungstate‐Photocatalyzed Dearomative Hydroacylation of Indoles: Direct Synthesis of 2‐Acylindolines

“…In recent years, visible light‐induced catalytic hydroacylation processes for the purpose of introducing carbonyl groups to π‐systems enjoyed a lot of methodological developments [9] . Among them, hydrogen atom transfer (HAT) involving aldehydes as acyl radical sources under mild reaction conditions has become a strategy of choice [9c–g,j,o–r,w] . In particular, contrary to classical ruthenium‐ and iridium‐photoactivable complexes, decatungstate anion ([W 10 O 32 ] 4− ) – belonging to the family of polyoxometalate species (POMs) – does not require a cocatalyst to realize such hydrogen atom abstractions.…”

Brønsted Acid-Promoted Intermolecular Dearomative Photocycloaddition of Bicyclic Azaarenes with Olefins under Aerobic Conditions

“…For example, olefin hydrogenation with H 2 -Pd/C gave tricyclic pyridine 44 in moderate yield. The keto group-containing pyridine 45 was isolated in 51% yield via photocatalytic olefin hydroacylation of 2 with butanal . Furthermore, upon treatment of 2 with m- CPBA, epoxide 46 was obtained in 91% yield.…”

Photocatalytic Incorporation of an Oxime Ether Functional Group at Inert C(sp3)–H Bonds via HAT

“…Light-induced hydrogen atom transfer (HAT) catalysis has emerged as a powerful strategy for the selective functionalization of C–H bonds . Recently, our group reported the light-induced radical hydroacylation of olefins and C–H functionalization of abundant chemicals using diaryl ketone as a HAT catalyst . Following these studies, we envisaged that a photocatalytic method for the synthesis of functionalized oximes could be developed using a suitable sulfone-oxime to intercept the carbon radical generated via direct HAT from substrates to the photoexcited catalyst.…”