Construction of cyclopenta[ b ]dihydronaphthofurans via TsOH-catalyzed consecutive biscyclization of dithioallylic alcohols and 1-styrylnaphthols.

An efficient TsOH-catalyzed consecutive biscyclization cascade reaction of dithioallylic alcohols with 1-styrylnaphthols is demonstrated for the concise construction of pharmaceutically important cyclopenta[ b ]dihydrobenzofuran scaffolds. This process involved an acid-catalyzed (3+2) cycloaddition followed by an intramolecular nucleophilic addition, providing cyclopenta[ b ]dihydronaphthofurans bearing a tetra- or fully substituted cyclopentane core in good yields with exclusive diastereoselectivities (>20 : 1 d.r.).