Unexpected regio- and chemoselectivity of cationic gold-catalyzed cycloisomerizations of propargylureas: access to tetrasubstituted 3,4-dihydropyrimidin-2(1H)-ones
作者:Olga P. Pereshivko、Vsevolod A. Peshkov、Anatoly A. Peshkov、Jeroen Jacobs、Luc Van Meervelt、Erik V. Van der Eycken
DOI:10.1039/c3ob42221f
日期:——
Cationic gold-catalyzed cycloisomerizations of propargylureas, derived in situ from secondary propargylamines and aryl or alkyl isocyanates, have been studied. The reaction outcome was found to be different from what was previously observed for the tosyl isocyanate-derived ureas in terms of both regio- and chemoselectivity. As a result, the current protocol offers efficient access to the 3,4-dihydropyrimidin-2(1H)-one core through the 6-endo-dig N-cyclization.
Tetrasubstituted 2-Imidazolones via Ag(I)-Catalyzed Cycloisomerization of Propargylic Ureas
作者:Vsevolod A. Peshkov、Olga P. Pereshivko、Sweta Sharma、Thirumal Meganathan、Virinder S. Parmar、Denis S. Ermolat’ev、Erik V. Van der Eycken
DOI:10.1021/jo200789t
日期:2011.7.15
A one-pot protocol based on a Ag(I)-catalyzed cycloisomerization of propargylic ureas, derived from secondary propargylamines and isocyanates, was developed for the generation of the 2-imidazolone core.