Convenient Synthesis of Thioester‐Substituted Oxindoles by Palladium‐Catalyzed Thiocarbonylative Cyclization with Sulfonyl Chlorides as the Sulfur Source

Abstract

A general and straightforward strategy for the synthesis of thioester-substituted oxindoles via a palladium-catalyzed thiocarbonylative cyclization process has been developed. With sulfonyl chlorides as promising sulfur source, a wide range of thioester-substituted oxindoles were obtained in moderate to high yields. Both aryl and alkyl sulfonyl chlorides were well tolerated, and Mo(CO) 6 played a dual role as both a CO source and a reductant in this approach.

Palladium-Catalyzed Three-Component Cascade Carbonylation Reaction to Construct Benzofuran Derivatives

“…In particular, the palladium-catalyzed domino carbonylation reaction is favored by many scientific researchers (Scheme c). Correia, Zhang, Zhu, Guan, Yao, and other groups have successively realized the palladium-catalyzed domino Heck-cyclization reaction, which provided a series of five-, six-, or even seven-membered heterocyclic carbonyl derivatives.…”

Carbonylative Transformations Using a DMAP-Based Pd-Catalyst through Ex Situ CO Generation

“… Transition-metal-catalyzed carbonylative transformations have contributed to the facile insertion of carbonyl moieties over the past decades . The key areas of research include circumventing the use of toxic CO gas and finding cheap CO surrogates, safe and easy handling through the use of a two-chamber reactor (COware), finding novel catalytic systems, and avoiding the use of phosphine ligands . Though most efficient carbonylative transformations require the use of bidentate phosphine ligands such as Xantphos, dppf, DPEphos, etc., there are certain limitations of using phosphines in homogeneous catalysis: (a) difficulty in handling due to air- and moisture-sensitivity; (b) high cost, sometimes comparable or superior to the palladium catalyst itself; (c) slight recyclability due to their homogeneous and sensitive nature; (d) difficulty in purification of the final product due to the presence of phosphine oxide, and (e) complicated and time-consuming synthetic procedure. , …”

Visible Light-Accelerated Palladium-Catalyzed Thiocarbonylation Using Oxalic Acid Monothioester with Aryl/Alkenyl Sulfonium Salts

“…Thioesters, as an important synthetic intermediate, are a class of biologically significant compounds that are widely used in the synthesis of complex bioactive molecules and natural products, such as peptides and amino acids, due to their excellent properties of high chemoselectivity. Additionally, thioesters can also be used as important synthetic intermediates for the synthesis of other compounds, such as ketones, ethers, alcohols, and amides . Therefore, the synthesis of thioesters has received a lot of attention from chemists.…”