Inverse electron-demand 1,3-dipolar cycloaddition reactions of cyclooctyne with pyridinium bis(methoxycarbonyl)methylides

Cyclooctyne underwent 1,3-dipolar cycloaddition with pyridinium bis(methoxy-carbonyl)methylides to afford the corresponding indolizines (8-methoxycarbonyl-7-azatricyclo[7.6.0.02-7]pentadeca-1,3,5,8-tetraenes) in good to moderate yields. Some molecular orbital considerations are also described on this reaction compared with the results on the reaction of pyridinium dicyanomethylides with cyclooctyne.