Studies On The Reaction Of Aza-oxyallylic Cation With Unsaturated Aldehydes,Istains And Vinylogous Imines

The oxazolidin-4-ones are key structural motifs found in natural products and bioactive molecules.The synthesis of oxazolidin-4-ones derivatives has received much attention due to their bioactivities and medicinal value.The synthesis methods can be devided into four categories: 1)Cycloaddition reactions of oxaziridines with ketenes,azlactones,and ammonium enolates.2)Photoelimination reactions of ?-keto amides.3)Retro-Claisen condensation reaction between enol ethers and ?-bromoamido alcohols.4)Condensation reactions between ?-hydroxyamides and carbonylcompounds.A new [3+2] cycloaddition reaction of ?,?-unsaturated aldehydes and ?-haloamides,which efficient to oxazolidin-4-ones has been developed.Azaoxyallyl cations were formed in situ from ?-haloamides.The cycloaddition reaction of ?,?-unsaturated aldehydes and azaoxyallyl cations provided a five-membered oxazolidin-4-ones in 90-95% yields.Under the optimal conditions,the reaction scope was investigated.The relative configuration of products were identified by X-ray analysis.We also studied the [3 + 2] cycloaddition reaction between azaoxyallyl cations and isatins to afford the spiroxazolidin-4-ones derivatives in up to 96% yield.The optimal reaction conditions were obtained by sifting the reaction conditions such as base,solvent and temperature.And then,the reaction scope was investigated.Various isatins were compatible.The relative configuration of products were identified by X-ray analysis.The reaction between azaoxyallyl cations and electron-deficient vinylogous imines,consequently producing 3-indolyl methanamine bearing multiple functional groups in up to 93% yield,has been developed.The optimal reaction conditions were obtained by sifting the reaction conditions such as base,solvent and temperature.The reaction scope was investigated under the optimal conditions.Various benzene sulfonylindoles were compatible affording the corresponding 3-indolyl methanamine derivatives in good yields.The relative configuration of products were identified by X-ray analysis.