Lewis acid-catalyzed atom transfer radical cyclization of unsaturated β-keto amides
作者:Dan Yang、Yi-Long Yan、Ka-Lun Law、Nian-Yong Zhu
DOI:10.1016/j.tet.2003.06.009
日期:2003.12
acid-catalyzed atom transfer radical cyclization reactions of olefinic α-bromo β-keto amides were investigated. It was found Lewis acid Yb(OTf)3 or Mg(ClO4)2 not only promoted the cyclization reactions, but also resulted in excellent trans stereocontrol in the cyclization products. With the catalysis of Lewis acid Yb(OTf)3 or Mg(ClO4)2 at −78°C in the presence of Et3B/O2, the cyclization reactions of C-olefinic
研究了路易斯酸催化的烯烃α-溴β-酮酰胺的原子转移自由基环化反应。发现路易斯酸Yb(OTf)3或Mg(ClO 4)2不仅促进环化反应,而且在环化产物中产生优异的反式立体控制。在Et 3 B / O 2存在下,路易斯酸Yb(OTf)3或Mg(ClO 4)2在-78°C下催化,C-烯烃β-酮酰胺的环化反应提供了环酮,而N的环化反应烯烃的β-酮酰胺导致形成γ-内酰胺,其可被转化为3-氮杂-双环[3,1,0]己-2-基。