A cascade double 1,4-addition/intramolecular annulation strategy for expeditious assembly of unsymmetrical dibenzofurans

Existing routes to dibenzofurans have intrinsic regioselectivity, limiting the substitution patterns available in the products. Here a double 1,4-conjugate addition-annulation cascade between propargylamines and imidazolium methylides provides direct access to dibenzofurans with a complementary substitution pattern.