Rhodium-Catalyzed Direct C−H Addition of 3,4-Dihydroquinazolines to Alkenes and Their Use in the Total Synthesis of Vasicoline
作者:Sean H. Wiedemann、Jonathan A. Ellman、Robert G. Bergman
DOI:10.1021/jo052345b
日期:2006.3.1
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
报道了用Rh(I)催化剂将未活化烯烃与3,4-二氢喹唑啉进行分子间和分子内偶联。发现在存在Rh(I)/ PCy 3的情况下,烯烃与NH -3,4-二氢喹唑啉之间的偶联会随着杂环脱氢而连续发生/ HCl催化剂。该反应被用于开发通过氧化后处理步骤合成2-取代的喹唑啉的有效方法。还描述了链连接的3,4-二氢喹唑啉的区域控制合成和Rh催化的环化反应。应用该方法,完成了第二个全合成的vasicoline合成。通过使用刚性双环膦配体,可以使关键的Rh催化环化步骤成为可能。该合成进一步证明了邻位取代的芳基氯的具有挑战性的Cu催化的酰胺化。