Copper/silver-mediated cascade reactions for the construction of 2-sulfonylbenzo[b]furans from trans-2-hydroxycinnamic acids and sodium sulfinates.

Efficient construction of 2-sulfonylbenzo[b]furans is achieved from readily available trans-2-hydroxycinnamic acids and sodium sulfinates mediated by the CuCl2·2H2O/AgTFA system under mild conditions. This unprecedented synthetic protocol provides expedient access to a series of products in one step via a protodecarboxylation/C-S bond formation/C-O bond formation cascade.