Facile Synthesis of Indolizines via 1,3-Dipolar Cycloadditions in [Omim]Br: The Promotion of the Reaction through Noncovalent Interactions

Various indolizines are synthesized through one-pot, two-step 1,3-dipolar cycloadditions in recyclable [Omim]Br with high yields and a broad substrate scope. The promotion of noncovalent interactions between ionic liquids and substrates or intermediates on the reaction is discovered on the basis of the results of control and NMR experiments. Moreover, the 3-arylindolizines can also be prepared from low-activity arylmethylpyridinium ylides in the protocol.