NHC-Stabilized Gold(I) Complexes: Suitable Catalysts for 6-<i>exo</i>-dig Heterocyclization of 1-(<i>o</i>-Ethynylaryl)ureas
作者:Ana Gimeno、Mercedes Medio-Simón、Carmen Ramírez de Arellano、Gregorio Asensio、Ana B. Cuenca
DOI:10.1021/ol100595s
日期:2010.5.7
3-substituted 1-(o-ethynylaryl)ureas 1 selectively undergo either 6-exo-dig or 5-endo-dig cyclization (to give 4-methylene-3,4-quinazolin-2-ones 2 or indoles 3, respectively) depending on the choice of the metal, ligand, and reaction conditions. The best results (up to 96% yield) in the preparation of the hydroamination products 2 are achieved with the highly bulky NHC-stabilized cationic gold(I) complex