The Brönsted acid-catalyzed cascade synthesis of densely substituted benzofurans from easily available salicyl alcohols and biomass-derived furans has been developed. The disclosed sequence includes the intermediate formation of 2-(2-hydroxybenzyl)furans that quickly rearrange into functionalized benzofurans. The established protocol was applied for the total synthesis of sugikurojinol B.

A CuBr2-catalyzed alkylation of furans with a broad scope of benzyl alcohols and benzaldehydes is reported. Reaction proceeds efficiently under mild reaction conditions requiring no inert atmosphere or other precautions. Moreover, it is shown that CuBr2 catalyzes domino reactions of furans with benzyl alcohols or benzaldehydes bearing a nucleophilic moiety in the ortho-position. These protocols offer a practical approach to densely substituted heterocyclic motifs from easily available furans.