HFIP‐Mediated Desulfinative Friedel–Crafts Cyclobutenylation Reaction.

In 1,1,1,3,3,3‐hexafluoroisopropyl alcohol (HFIP), gem‐bis(triflyl)cyclobutenes, which can be prepared by the (2+2) cycloaddition reaction of Tf2C=CH2 with alkynes, underwent desulfination to generate the corresponding cyclobutenyl cation. This unique reactivity was successfully applied to the Friedel–Crafts type cyclobutenylation reaction of several (hetero)aromatic compounds. [ABSTRACT FROM AUTHOR]