Organophosphane-Catalyzed Direct β-Acylation of 4-Arylidene Pyrazolones and 5-Arylidene Thiazolones with Acyl Chlorides
作者:Pankaj V. Khairnar、Yin-Hsiang Su、Yung-Chang Chen、Athukuri Edukondalu、Yi-Ru Chen、Wenwei Lin
DOI:10.1021/acs.orglett.0c02408
日期:2020.9.4
An efficient method for the direct β-acylation of arylidene pyrazolones and thiazolones with acyl chlorides in the presence of a base catalyzed by organophosphanes is reported. A variety of functionalized 4-arylidene pyrazolone and 5-arylidene thiazolonederivatives were prepared under metal-free and mild conditions via a tandem phospha-Michael addition/O-acylation/intramolecular cyclization/rearrangement
An inverse-electron-demand oxa-Diels–Alder reaction of 5-alkenyl thiazolones with β,γ-unsaturated carbonyl compounds enabled by quinine thiourea was studied, which allows the enantioselective synthesis of a broad range of highly functionalized pyranthiazoles bearing three continuous stereocenters. This protocol is adaptable to a wide scope of substrates and has great potential for scale-up synthesis
We have developed an organocatalyzedasymmetric three‐component reaction of thiazol‐4‐ones, acrolein and nitroolefins, which provides an efficient approach to access optically active spiro thiazol‐4‐ones. Under the catalysis of a bifunctional squaramide derived from L‐tert‐leucine, the reactions of a wide range of thiazol‐4‐ones, acrolein and nitroolefins took place smoothly to generate the corresponding