Efficient syntheses of 3,3-difluorooxindoles and 3-fluorooxindoles via fluorination of hydrazonoindolin-2-one with Selectfluor are reported. Under different solvent conditions, this method produced 3,3-difluorooxindoles and 3-fluorooxindoles selectively. The broad substrate scope and mild reaction conditions make this transformation a valuable method in drug discovery and development.
Direct Conversion of Indoles to 3,3-Difluoro-2-oxindoles <i>via</i> Electrophilic Fluorination
作者:Yee Hwee Lim、Qunxiang Ong、Hung A. Duong、Tuan Minh Nguyen、Charles W. Johannes
DOI:10.1021/ol302666d
日期:2012.11.16
3,3-Difluoro-2-oxindoles can be obtained directly from indoles in moderate yields via electrophilic fluorination using N-fluorobenzenesulfonimide as a mild fluorinating reagent. The presence of tell-butyl hydroperoxide during the reaction, together with additional heating after quenching the reaction with triethylamine, is beneficial to the formation of the desired product.