Integrated continuous‐flow/batch protocol for ortho‐selective alkynylation of (hetero)aryl tosylates

Abstract

AbstractThe ortho‐selective alkynylation of polyhalo‐substituted (hetero)aryl tosylates was investigated using an integrated continuous‐flow/batch protocol. Without the elimination of the tosyloxy group, the regioselective ortho‐metalation of the (hetero)aryl tosylates employing n‐BuLi and ZnCl2 was successfully achieved in continuous‐flow chemistry within 10.92 s (residence time). The Pd‐catalyzed Negishi alkynylations of various iodoethynyl (hetero)arenes and the resulting arylzinc species proceeded at room temperature in yields ranging from 51% to 95%. Finally, the synthetic utility of this strategy was validated by the synthesis of benzofuran and pyridofuran derivatives.