1,3-Dipolar Cycloaddition of Nitriles under Microwave Irradiation in Solvent-Free Conditions
摘要:
Several nitriles were allowed to react with nitrones or nitrile oxides in the absence of solvent under microwave irradiation within 2-10 min to give 2,3-dihydro-1,2,4-oxadiazoles or 1,2,4-oxadiazoles, respectively.
1,3-Dipolar cycloaddition of nitrones with nitriles.
作者:Pedro H.H. Hermkens、Jan H.v. Maarseveen、Chris G. Kruse、Hans W. Scheeren
DOI:10.1016/s0040-4020(01)89838-0
日期:——
nitriles 14–16, proceeded under thermal as well as underhighpressure conditions with complete regioselectivity to give Δ4-1,2,4-oxadiazolines 17–19. In general, the cycloaddition seemed to be controlled by a HOMO(nitrone)- LUMO(nitrile) interaction. However, a crossover in the orbital control is probable observed with nitrile 16c. Nitrone-nitrile cycloadditions are normal typeII cycloadditions so that