Chelation-assisted C-S activation/cascade heteroannulation of pyridine-2-thione derivatives in Pd-catalyzed cross-coupling reaction with alkynes

Ortho-chelation assistance was proved to be crucial for the success of the desulfitative Sonogashira cross-coupling reaction of thioamide-type pyridine derivatives and alkynes. Corresponding alkynylated products were obtained with moderate to excellent yields. Thanks to this reaction, furo[3,2-b]pyridine and 1H-pyrrolo[3,2-b]pyridine derivatives were synthesized through a one-pot cross-coupling reaction/heteroannulation sequence.

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