A Practical Synthesis of 3-Acyl Cyclobutanones by [2 + 2] Annulation. Mechanism and Utility of the Zn(II)-Catalyzed Condensation of α-Chloroenamines with Electron-Deficient Alkenes
作者:Jeannette M. O’Brien、Jason S. Kingsbury
DOI:10.1021/jo102257k
日期:2011.3.18
New conditions for the conversion of simple tertiary amides to α-chloroenamines and their use in Zn(II)-catalyzed cycloaddition reactions with commercial α,β-unsaturated carbonyl compounds allows rapid, regiocontrolled access to 3-acyl cyclobutanones. Reactions take place at ambient temperature without solvent, giving strained [2 + 2] adducts with all-carbon-substituted quaternary carbon atoms. Ab
将简单的叔酰胺转化为α-氯亚胺的新条件,以及它们在Zn(II)催化的与商业α,β-不饱和羰基化合物进行的环加成反应中的使用,可以快速,区域控制地获得3-酰基环丁酮。反应在无溶剂的环境温度下进行,得到带有全碳取代的季碳原子的应变[2 + 2]加合物。假定的酮亚胺中间体的重算从头计算以及苯乙烯基烯烃的研究表明,Zn(OTf)2在催化过程中具有双重作用。