Olefins to 4,5-Dihydro-l,3-oxazoles

Olefins react with benzenetellurinyl trifluoroacetate in acetonitrile in the presense of boron trifluoride etherate to give 2-acetaminoalkyl phenyl tellurium oxides that are converted, upon treatment with triethylamine in tetrahydrofuran at 30° for 4 h, to 4,5-dihydro-l,3-oxazoles. These highly regio- and stereoselective reactions allow the one-pot, high-yield conversion of olefins to 1,3-oxazoles. Ethyl cyanide and phenyl cyanide can be used instead of acetonitrile. 

Similarly prepared were the following 4,5-dihydro-l,3-oxazoles  

When the addition of benzenetellurinyl trifluoroacetate to an olefin is carried out in 1,2-dichloroethane in the presence of ethoxycarbonylcyanamide and the resultant addition product heated at 75° for 3 h, ethoxycarbonylamino-substituted 4,5-dihydro-l,3-oxazoles were obtained  

Irgolic Organo Tellurium Compounds with 2 Te—C Bonds or 1 Te = C Bond 

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