Fe(OTf)3-mediated synthesis of sulfonyl dihydropyrans

Fe(OTf)3-mediated one-pot (3+3) cycloaddition of β-ketosulfones 1 with prenyl alcohol (2) in MeNO2 affords sulfonyl dihydropyrans 5 in good yields via a sequential intermolecular α-prenylation followed by intramolecular Friedel–Crafts alkylation. The method provides a highly effective condition.

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