Decarbonylative thioetherification by nickel catalysis using air- and moisture-stable nickel precatalysts

Abstract

A general, highly selective method for decarbonylative thioetherification of aryl thioesters by C-S cleavage is reported. These reactions are promoted by a commercially-available, user-friendly, inexpensive, air- and moisture-stable nickel precatalyst. The process occurs with broad functional group tolerance, including free anilines, cyanides, ketones, halides and aryl esters, to efficiently generate thioethers using ubiquitous carboxylic acids as ultimate cross-coupling precursors (cf. conventional aryl halides or pseudohalides). Selectivity studies and site-selective orthogonal cross-coupling/thioetherification are described. This thioester activation/coupling has been highlighted in the expedient synthesis of biorelevant drug analogue. In light of the synthetic utility of thioethers and Ni(ii) precatalysts, we anticipate that this user-friendly method will be of broad interest.

Synergistic Activation of Amides and Hydrocarbons for Direct C(sp3)–H Acylation Enabled by Metallaphotoredox Catalysis

“…To design a viable catalytic system, Ni/Ir based metallaphotoredox catalytic system was deemed particularly attractive. The high proficiency of Ni 0 species to undergo oxidative addition and the recent advances in C−H activation mediated by the catalytic generation of a chlorine atom under photocatalytic conditions were both considered suitable due to the high bond dissociation free energy of H−Cl (97 kcal mol −1 ) exceeding those of simple alkanes (91 kcal mol −1 for cyclohexane) . After assessing a variety of organic and transition‐metal photosensitizers, ubiquitous iridium phenylpyridine based photocatalyst Ir[dF(CF 3 )ppy] 2 (dtbbpy)PF 6 was found to be solely effective (Table S1 in the Supporting Information) .…”

Nickel‐Catalyzed Intramolecular Decarbonylative Coupling of Aryl Selenol Esters

“…Significant effort has also been devoted to the transition‐metal‐catalyzed decarbonylative intramolecular couplings of ketones, esters, and other carboxylic acid derivatives to form C−C and C‐heteroatom bonds [34–49] . Herein, we report our findings on an alternate synthetic route to diaryl selenides via the nickel‐catalyzed intramolecular decarbonylative coupling of selenoesters (Scheme 1).…”

Forging C−S(Se) Bonds by Nickel‐catalyzed Decarbonylation of Carboxylic Acid and Cleavage of Aryl Dichalcogenides

“…In particular, the nickel‐catalyzed decarbonylation reaction has been extensively explored by various research groups [7,8] . For instance (Scheme 1), in 2018, Szostak's research group reported the use of air and moisture‐stable nickel precatalysts to convert thioesters into thioethers by decarbonylation [9] . In the same year, Rueping's research group disclosed a new and selective cross‐coupling reaction of esters and amides with mercaptans as coupling partners [10] .…”