Gold-Catalyzed Cyclization and Subsequent Arylidene Group Transfer of O-Propioloyl Oximes
摘要:
Gold-catalyzed cyclizations of O-propioloyl oximes via C-N bond formation followed by arylidene group transfer were successfully carried out to afford the corresponding 4-arylideneisoxazol-5(4H)-ones in good to excellent yields. As an example, (E)-benzaldehyde O-3-phenylpropioloyl oxime (1a) was reacted in acetonitrile at 25 degrees C in the presence of Au(PPh(3))NTf(2) (5 mol %) to give 4-benzylidene-3-phenylisoxazol-5(4H)-one (2a) in 90% yield. On the basis of crossover experiments, the arylidene "migration" was shown to proceed in an intermolecular manner.
The reaction between nitrile oxides and 4-diphenylmethylene-3phenylisoxazol-5-one (5) proceeds in an unprecedented fashion to yield 4-diphenylmethylene-2,3,3-trisubstituted derivatives (10). Their structure was determined by an X-Ray diffraction study.
Gold-Catalyzed Cyclization and Subsequent Arylidene Group Transfer of <i>O</i>-Propioloyl Oximes
作者:Itaru Nakamura、Masashi Okamoto、Masahiro Terada
DOI:10.1021/ol100581m
日期:2010.6.4
Gold-catalyzed cyclizations of O-propioloyl oximes via C-N bond formation followed by arylidene group transfer were successfully carried out to afford the corresponding 4-arylideneisoxazol-5(4H)-ones in good to excellent yields. As an example, (E)-benzaldehyde O-3-phenylpropioloyl oxime (1a) was reacted in acetonitrile at 25 degrees C in the presence of Au(PPh(3))NTf(2) (5 mol %) to give 4-benzylidene-3-phenylisoxazol-5(4H)-one (2a) in 90% yield. On the basis of crossover experiments, the arylidene "migration" was shown to proceed in an intermolecular manner.
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