­Mn‐Catalyzed Dehydrocyanative Transannulation of Heteroarenes via C‐H Activation: Beyond the Permanent Directing Effects of Pyridines/Pyrimidines

Pyridine/pyrimidine rings are common and effective directing groups for catalytic activation of C‐H bonds. However, they are poorly functionalizable either under in situ or ex situ conditions. Reported in this work is Mn‐catalyzed dehydrocyanative transannulation between three classes of heteroarenes and propargyl carbonates. The pyridyl/pyrimidyl groups in the heteroarenes initially function as a directing group to enable C‐H allenylation; they then undergo intramolecular Diels‐Alder‐retro Diels‐Alder reactions with the allene moiety to afford fused carbo/heterocycles. Three key intermediates at different stages of the reaction have been isolated.

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