Catalyst-Controlled Regioselective Suzuki Couplings at Both Positions of Dihaloimidazoles, Dihalooxazoles, and Dihalothiazoles
作者:Neil A. Strotman、Harry R. Chobanian、Jiafang He、Yan Guo、Peter G. Dormer、Christina M. Jones、Janelle E. Steves
DOI:10.1021/jo100148x
日期:2010.3.5
dihaloazoles can be monoarylated at a single C−X bond with high selectivity via Suzukicoupling. By changing the palladium catalyst employed, the selectivity can be switched for some dihaloazoles, allowing for Suzukicoupling at the other, traditionally less reactive C−X bond. These conditions are applicable to coupling of a wide variety of aryl-, heteroaryl-, cyclopropyl-, and vinylboronic acids with
Tempering the Reactivities of Postulated α-Oxo Gold Carbenes Using Bidentate Ligands: Implication of Tricoordinated Gold Intermediates and the Development of an Expedient Bimolecular Assembly of 2,4-Disubstituted Oxazoles
作者:Yingdong Luo、Kegong Ji、Yuxue Li、Liming Zhang
DOI:10.1021/ja307948m
日期:2012.10.24
2,4-Oxazole is an important structural motif in various natural products. An efficient modular synthesis of this structure has been achieved via a [3 + 2] annulation between a terminal alkyne and a carboxamide using a gold-catalyzedoxidation strategy. The postulated reactive intermediate, a terminal α-oxo gold carbene, previously known to be highly electrophilic and hence unlikely to be trapped by