Tandem sp3 C-H functionlization/decarboxylation of 2-alkylazaarenes with coumarin-3-carboxylic acids.

The catalyst-free sp(3) C-H functionalization of 2-alkylazaarenes has been achieved in the reaction with (thio)coumarin-3-carboxylic acids. Followed by a tandem decarboxylation, this method provides facile synthesis of biologically important azaarene-substituted 3,4-dihydro(thio)coumarins in a single step in high yields.