s alkylation of indoles has been achieved in a one-pot process to produce 2,5-disubstitutedfurans using gallium-catalyzed sequential nucleophilic addition onto metal-activated 1-alkynyl-2,3-epoxy acetates. The reaction proceeds efficiently under mild conditions with complete regioselectivity to afford the substituted furan derivatives in good yields with high diversity.
A simple and convenient synthetic approach to difurylmethane derivatives has been developed via gold-catalyzedcycloisomerization of 1-oxiranyl-2-alkynyl esters and dimerization of the 2-(α-hydroxyalkyl)furans. The reaction takes place in the presence of 2 mol% of tetrachloroauric acid tetrahydrate (HAuCl4⋅4 H2O) under very mild conditions.