Visible Light Mediated Synthesis of Oxindoles

Abstract

Functionalized oxindoles are privileged heterocyclic scaffolds and common core structural motifs that are broadly present in numerous natural products and serve as key intermediates in the synthesis of biological products, agrochemicals, and pharmaceuticals. Oxindoles exhibit a broad pharmacological and physiological activities, and diverse range of applications in medicinal chemistry and biomedical research. Owing to these fascinating biological and physiological activities of oxindoles, several methodologies have been developed for the construction of oxindoles. In the past decade, the visible light mediated methodologies have attracted substantial attention and emerged as a promising approach for the construction of oxindoles. In this review, the visible light mediated synthesis of oxindoles have been described.

Green and sustainable visible light-mediated formation of amide bonds: an emerging niche in organic chemistry

“…48–52 The key concept of these photoredox catalyzed strategies is the use of a single-electron transfer process (SET) to generate a variety of radical species from the respective radical precursors via either oxidative- or reductive quenching of the photocatalyst, which upon a series of SET or HAT (hydrogen atom transfer) events, deliver the desired products. 53,54 In the past few decades, several elegant reviews have been documented in the literature for the development of amides. 55 In this review, we have presented recent breakthroughs and advancements in amide synthesis via these modern strategies.…”

Visible-light-induced radical cascade reaction to prepare oxindoles via alkyl radical addition to N-arylacryl amides

“…Li and co-workers 30 reported a palladium-catalyzed cyclization of N-arylacrylamides with activated alkyl bromides under thermal reaction conditions (Scheme 1b). Recently, some photocatalytic strategies have been reported for the synthesis of fluoro-containing oxindoles using ruthenium or iridium complexes as photocatalysts, [31][32][33][34][35][36][37] in which radical precursors including Umemoto's reagent, Togni's reagent, fluoro-containing sulfonyl chlorides, sulfinates, iodoalkanes and phosphonates were employed (Scheme 1c).…”

4‐Hydroxycoumarin: A Versatile Substrate for Transition‐metal‐free Multicomponent Synthesis of Bioactive Heterocycles

“…The preparation of coumarins and several 4‐hydroxycoumarin derivatives has been reviewed by Medina et al ., [33] Gaudino et al ., [34] Singh and Sharma, [35] Jung et al ., [36] Abdou et al [37] . Some examples of multicomponent reactions of 4‐hydroxycoumarin have been reviewed [38a–e] .…”