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.
阳离子金催化的丙炔基脲的环异构化反应已经研究,这些脲是通过在位合成的次级丙炔基胺和芳基或烷基异氰酸酯获得的。研究发现,该反应的结果与之前观察到的来自托磺酰异氰酸酯衍生的脲在区位选择性和化学选择性方面有所不同。因此,目前的方案通过6-内环-双N环化反应有效地获得了3,4-二氢吡咯并-2(1H)-酮的核心结构。