Asymmetric approach to the pentacyclic skeleton of Aspidosperma alkaloids via enantioselective intramolecular 1,3-dipolar cycloaddition of carbonyl ylides catalyzed by chiral dirhodium(II) carboxylates
作者:Hisanori Nambu、Mayuka Hikime、Janagiraman Krishnamurthi、Megumi Kamiya、Naoyuki Shimada、Shunichi Hashimoto
DOI:10.1016/j.tetlet.2009.03.142
日期:2009.7
describes asymmetric tandem carbonyl ylide formation–intramolecular 1,3-dipolar cycloaddition reaction of diazo imides containing a tethered indole catalyzed by chiral dirhodium(II) carboxylates as an approach to the pentacyclic skeleton of Aspidosperma alkaloids. The cycloaddition of carbonyl ylides derived from indolyl-substituted 2-diazo-5-imido-3-ketoesters under the influence of dirhodium(II) tetr
这封信描述了不对称串联羰基叶立德的形成-重氮天青(II)羧酸盐催化的重链吲哚的重氮酰亚胺的分子内1,3-偶极环加成反应,作为一种方法来对曲霉生物碱的五环骨架进行研究。在四(二)N [ N-四氯邻苯二甲酰基- (S)-叔亮氨酸酯],Rh 2(S -TCPTTL )的影响下,吲哚基取代的2-重氮-5-亚氨基-3-酮酸酯衍生的羰基环的环加成反应)4,提供中等收率和高达66%ee的对映选择性以及完美的内环的环加合物非对映选择性。这是在吲哚基π键上羰基内酰胺的分子内环加成中的不对称诱导的第一个例子。