Facile Synthesis of 4-(Trifluoromethyl)-1H-isochromenes from Alkynols

Isochromene derivatives are important structural motifs found in various biologically active compounds as well as important natural products. A method to generate CF3-containing isochromene derivatives has been developed, which gives moderate to good yields by using Togni's reagent as the trifluoromethyl source. The key step involves alkynol cyclization and subsequent trapping by a reactive electrophilic trifluoromethyl species generated insitu from Togni's reagent.