Regio- and stereoselective synthesis of thiazoline derivatives <i>via</i> the thioketene-induced ring expansion of aziridines
作者:Qiuyue Wu、Jiaxi Xu
DOI:10.1039/d1cc06535a
日期:——
Metal-free thioketene-induced ring expansion of aziridines gave 4-alkylthiazolines stereospecifically from 2-alkylaziridines through an intramolecular substitution at the less substituted ring carbon and 5-arylthiazolines stereoselectively from 2-arylaziridines via tandem ring cleavage and formation through intimate ion-pair intermediates after nucleophilic addition of aziridines to thioketenes generated
A photocatalyzed formal (3+2) cycloaddition has been developed to construct original polysubstituted α‐SCF3 cyclopentanones in a regio‐ and diastereoselective manner. This building block approach leverages trifluoromethylthio alkynes and branched / linear aldehydes, as readily available reaction partners, in consecutive hydrogen atom transfers and C–C bond formations. Difluoromethylthio alkynes are also compatible subtrates. Furthermore, the potential for telescoped reaction starting from alcohols instead of aldehydes was demonstrated, as well as process automatization and scale‐up under continuous microflow conditions. This prompted density functional theory calculations to support a free radical‐mediated cascade hydrogen atom transfer process.