Direct esterification of carboxylicacids with arylboronic acids has been successfully developed employing methyl propiolate as an activating reagent. This transformation was performed through a process of enol ester intermediate‐induced metal‐free oxidative coupling. Metal‐free, simple operation, good functional group tolerance, all of these indicate that this method is an adoptable approach for the
Acylation of oxindoles using methyl/phenyl esters <i>via</i> the mixed Claisen condensation – an access to 3-alkylideneoxindoles
作者:Ramdas Sreedharan、Purushothaman Rajeshwaran、Pradeep Kumar Reddy Panyam、Saurabh Yadav、C. M. Nagaraja、Thirumanavelan Gandhi
DOI:10.1039/d0ob00789g
日期:——
Predominantly, aggressive acid chlorides and stoichiometric coupling reagents are employed in the acylating process for synthesizing carbonyl tethered heterocycles. Herein, we report simple acyl sources, viz. methyl and phenyl esters, which acylate oxindoles via the mixed Claisen condensation. This straightforward protocol is mediated by LiHMDS and KOtBu and successfully applied to a wide range of
Nickel-Catalyzed C−S Bond Formation via Decarbonylative Thioetherification of Esters, Amides and Intramolecular Recombination Fragment Coupling of Thioesters
A nickelcatalyzed cross‐coupling protocol for the straightforward C−Sbond formation has been developed. Various mercaptans and a wide range of ester and amide substrates bearing various substituents were tolerated in this process which afforded products in good to excellent yields. Furthermore, an intramolecular protocol for the synthesis of thioethers starting from thioesters has been developed
Ligand-Controlled Chemoselective C(acyl)–O Bond vs C(aryl)–C Bond Activation of Aromatic Esters in Nickel Catalyzed C(sp<sup>2</sup>)–C(sp<sup>3</sup>) Cross-Couplings
converted into the alkylated arenes and ketone products, respectively. The utility of this newly developed protocol was demonstrated by its wide substrate scope, broad functional group tolerance and application in the synthesis of keyintermediates for the synthesis of bioactive compounds. DFT studies on the oxidative addition step helped rationalizing this intriguing reaction chemoselectivity: whereas
Transition-Metal-Free Poly(thiazolium) Iodide/1,8-Diazabicyclo[5.4.0]undec-7-ene/Phenazine-Catalyzed Esterification of Aldehydes with Alcohols
作者:Supill Chun、Young Keun Chung
DOI:10.1021/acs.orglett.7b01617
日期:2017.7.21
Poly(3,4-dimethyl-5-vinylthiazolium) iodide was used as a polymer precatalyst in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and phenazine for the oxidative esterification of aldehydes with alcohols. Selective functionalization of OH groups was achieved in the presence of NH2 groups. The poly(thiazolium) iodide/DBU/phenazine system exhibited excellent catalytic activity and could be reused