Visible-light photoredox catalysis has been esteemed as one sustainable and attractive synthetic tool. In the past four years, a new yet challenging trend, visible-light-driven redox-neutral radical C–C cross-coupling involving putative radical intermediates, has been booming rapidly. Its advent brings a powerful platform to achieve non-classical C–C connections, and should lead to fundamental changes in retrosynthetic analysis. In this tutorial review, we highlight the recent achievements of visible-light-mediated redox-neutral radical C(sp³)–C(sp²), C(sp³)–C(sp), and C(sp³)–C(sp³) bond formation, opening a new window for C–C cross-coupling through the photoredox electron shuttling cycle between two coupling partners. While radical–radical coupling steered by the persistent radical effect was proposed as a rational explanation for the redox-neutral photoredox events, alternative kinetically driven chain propagation and radical addition pathways cannot be ruled out. This tutorial review aims to highlight the recent achievements of photoredox-neutral radical C–C coupling in synthetic chemistry.

The remote radical migration strategy has gained considerable momentum. During the past three years, we have witnessed the rapid development of sustainable and practical C–C and C–H bond functionalization by means of long-distance 1,n-radical migration (n = 4, 5, 6) events. Its advent brings our chemical community a new platform to deal with the challenging migration transformations and thus complements the existing ionic-type migration protocols. In this review, the recent achievements in distal radical migration triggered C–C and C–H bond functionalization are summarized.

The construction of an aryl ketone structural unit by means of catalytic carbon–carbon coupling reactions represents the state-of-the-art in organic chemistry. Herein we achieved the direct deoxygenative ketone synthesis in aqueous solution from readily available aromatic carboxylic acids and alkenes, affording structurally diverse ketones in moderate to good yields. Visible-light photoredox catalysis enables the direct deoxygenation of acids as acyl sources with triphenylphosphine and represents a distinct perspective on activation. The synthetic robustness is supported by the late-stage modification of several pharmaceutical compounds and complex molecules. This ketone synthetic strategy is further applied to the synthesis of the drug zolpidem in three steps with 50% total yield and a concise construction of cyclophane-braced 18–20 membered macrocycloketones. It represents not only the advancement for the streamlined synthesis of aromatic ketones from feedstock chemicals, but also a photoredox radical activation mode beyond the redox potential of carboxylic acids.