Phosphane- and Amine-Catalyzed Ring-Opening Reactions of Cyclopropenones with Isatin Derivatives: Synthesis of Carboxylated 1<i>H</i>-Indoles and Multisubstituted 2<i>H</i>-Pyran-2-ones
作者:Wen-Tao Zhao、Xiang-Ying Tang、Min Shi
DOI:10.1002/ejoc.201400077
日期:2014.5
The phosphane- and amine-catalyzedring-openingreactions of cyclopropenones with isatinderivatives give different reaction outcomes. Under phosphane catalysis, carboxylated1H-indoles are afforded in good yields, and under amine catalysis, multisubstituted2H-pyran-2-ones are provided in moderate yields. The mechanistic aspects of these reactions are discussed on the basis of control experiments
We report herein the Pd-catalyzed selective ring-opening reaction of cyclopropenones with vinyl epoxides. By using a commercially available Pd2(dba)3·CHCl3–BINAP catalyst, a wide range of conjugated alkadienyl carboxylates could be accessed in good yield and excellent regioselectivity. The new application of zwitterionic π-allyl palladium intermediates has been demonstrated in organic synthesis.