Strategic Use of Visible-Light Photoredox Catalysis in Natural Product Synthesis

Abstract

Recent progress in the development of photocatalytic reactions promoted by visible light is leading to a renaissance in the use of photochemistry in the construction of structurally elaborate organic molecules. Because of the rich functionality found in natural products, studies in natural product total synthesis provide useful insights into functional group compatibility of these new photocatalytic methods as well as their impact on synthetic strategy. In this review, we examine total syntheses published through the end of 2020 that employ a visible-light photoredox catalytic step. To assist someone interested in employing the photocatalytic steps discussed, the review is organized largely by the nature of the bond formed in the photocatalytic step.

Metalated covalent organic frameworks: from synthetic strategies to diverse applications

“…Visible-light photoredox catalysis is an invaluable tool in modern organic synthesis, in which light active metal-based catalysts (e.g., Ru-, Ir-, and Au-based complexes) with long excited-state lifetimes and high redox potentials allow the formation of radical intermediates, enabling substrate activation and driving the reaction. [639][640][641] Modification of photoredox catalysts on COF-scaffolds makes the visible-light heterogeneous catalysis available. For example, the Neogi group reported that the tris(2,2 0 -bipyridine)ruthenium(II)-derived Ru-TAPM-BPDCA-COF is a useful photoredox catalyst for the Strecker reaction (Fig.…”

Synthetic Applications of Photocatalyzed Halogen‐Radical Mediated Hydrogen Atom Transfer for C−H Bond Functionalization

“…[18] More recently, photocatalysis has emerged as an extremely valuable and versatile tool in organic synthesis because it allows the use of the greenest and cheapest form of energy (i. e. photons) for synthetic purposes. [8,19,28,[20][21][22][23][24][25][26][27] This happens thanks to the aid of a species that is purposely added to the reaction mixture, i. e. the photocatalyst (PC), which is responsible for converting light energy into chemical energy for substrate activation. A photocatalyzed version of HAT exists too, and can be classified into two main categories: direct HAT and indirect HAT (Scheme 1).…”

Electron donor–acceptor complex-catalyzed photoredox reactions mediated by DIPEA and inorganic carbonates

“…Since the donor or acceptor catalyst functions through the association with leaving group-bearing moieties, the EDA catalysis approach is selective and efficient as was demonstrated in the pioneering studies. It may also provide an alternative to photosensitizer-based classic photocatalysis 11 in certain cases.…”