Scheme 5. Cycloaddition with benzene SF₄-alkynes 6 and azide 4a. ^aReaction of 6 (0.5 mmol) was performed with 4a (1.5 mmol) in toluene at 110 °C for 24 h. ^bIsolated yield. ^cRatio of the two regioisomers A and B.