Photoredox Catalysis in Organic Chemistry

Abstract

In recent years, photoredox catalysis has come to the forefront in organic chemistry as a powerful strategy for the activation of small molecules. In a general sense, these approaches rely on the ability of metal complexes and organic dyes to convert visible light into chemical energy by engaging in single-electron transfer with organic substrates, thereby generating reactive intermediates. In this Perspective, we highlight the unique ability of photoredox catalysis to expedite the development of completely new reaction mechanisms, with particular emphasis placed on multicatalytic strategies that enable the construction of challenging carbon–carbon and carbon–heteroatom bonds.

Anthraquinones as Photoredox Catalysts for the Reductive Activation of Aryl Halides

“…[1][2][3][4][5][6][7][8][9] Ru-and Ir-based coordination complexes have received enormous attention because of their excellent visible-light-harvesting properties, modest to extremely high oxidation and reduction potentials, relatively long excited-state lifetimes, and reasonably good chemical and photostabilities under synthetic oxidative and reductive conditions. [2] In addition, considerable efforts have been made to develop metal-free photoredox catalytic methods with organic dyes [8,[10][11][12][13][14] such as eosin Y [10,11] or rhodamine derivatives [13,14] and organic heterogeneous photocatalysts [15] for synthetic transformations.…”

Visible‐Light Photocatalysis as an Enabling Tool for the Functionalization of Unactivated C(sp3)‐Substrates

“…[1] Over the past decade, visible-light photocatalysis has emerged as one of the most dynamic and powerful synthetic manifolds in today's synthetic chemistry landscape. [2][3][4][5][6][7][8][9][10][11][12][13][14] This is initial studies focused largely on the functionalization of stabilized radical intermediates, over the past few years significant efforts have been directed towards the functionalization of challenging unactivated radical precursors. In this review we summarize the recent developments in the use of visible-light photocatalysis for the functionalization of unactivated C(sp 3 )-substrates.…”

Radical‐Based C−C Bond‐Forming Processes Enabled by the Photoexcitation of 4‐Alkyl‐1,4‐dihydropyridines

“…We reasoned that this unique reactivity behavior could be fully exploited in the framework of a photochemical nickel‐catalyzed cross‐coupling method. Merging nickel catalysis14 and photoredox catalysis15 has recently emerged as a versatile platform for developing highly enabling cross‐coupling methods 16. The success of this approach relies on the ability of Ni 0 complexes to undergo facile oxidative addition with aromatic halides while engaging in radical‐capture mechanisms.…”