N-Heterocyclic Carbene-Catalyzed Remote Enantioselective C-C Bond Formation via 1,6-Addition with Formyl Enynes

N-Heterocyclic carbenes (NHCs) have emerged as powerful organocatalysts in controlling the stereoselectivities of the reaction sites that are remote from the catalyst-binding position. Meanwhile, the construction of a stereogenic center at the δ-position through NHC catalysis remains an unmet goal. Herein, we report the NHC-catalyzed enantioselective 1,6-conjugated addition reaction of formyl enynes with nucleophiles through an oxidative LUMO activation strategy. The reaction enables efficient chirality control at the δ-position of the formyl enyne substrates, providing access to high-value-added enantio-enriched pyrano[2,3-b]indole and pyrano[2,3-c]pyrazole derivatives. In addition, central-to-axial chirality transfer through the oxidation of our products was realized, enabling facile access to axially chiral pyrans.