Wiedemann Sean H, Ellman Jonathan A, Bergman Robert G
Department of Chemistry, University of California, Berkeley, California 94720, USA.
J Org Chem. 2006 Mar 3;71(5):1969-76. doi: 10.1021/jo052345b.
The inter- and intramolecular couplings of unactivated alkenes to 3,4-dihydroquinazolines with a Rh(I) catalyst are reported. Coupling between olefins and NH-3,4-dihydroquinazoline was found to occur consecutively with heterocycle dehydrogenation in the presence of a Rh(I)/PCy3/HCl catalyst. The reaction was used to develop an effective method for the synthesis of 2-substituted quinazolines through an oxidative workup step. The regiocontrolled synthesis and Rh-catalyzed cyclization of alkene-tethered 3,4-dihydroquinazolines are also described. Applying this method, the second total synthesis of vasicoline was achieved. The key Rh-catalyzed cyclization step was made possible by the use of a rigid bicyclic phosphine ligand. The synthesis further demonstrates a challenging Cu-catalyzed amidation of an ortho-substituted aryl chloride.
报道了未活化烯烃与Rh（I）催化剂作用下与3,4-二氢喹唑啉的分子间和分子内偶联反应。在Rh（I）/PCy3/HCl催化剂存在下，烯烃与NH-3,4-二氢喹唑啉之间的偶联反应与杂环脱氢反应连续发生。该反应被用于开发一种通过氧化后处理步骤合成2-取代喹唑啉的有效方法。还描述了烯烃连接的3,4-二氢喹唑啉的区域选择性合成和Rh催化的环化反应。应用该方法，实现了瓦西可林的第二次全合成。通过使用刚性双环膦配体，关键的Rh催化环化步骤得以实现。该合成还展示了具有挑战性的铜催化邻位取代芳基氯的酰胺化反应。
