Accessing Carbon, Boron and Germanium Spiro Stereocenters in a Unified Catalytic Enantioselective Approach

Achieving substrate generality in asymmetric catalysis is a long-standing goal, particularly for the selective construction of chiral heteroatoms. Compared to carbon, sulfur, phosphorus and silicon stereogenic centers, the methods for their boron and germanium congeners remain very scarce. Chiral (hetero) spirocycles are of relevance in several research domains. Methods effective for constructing carbon-centered chiral spirocycles do not translate to boron and germanium, leaving these chiral centers unexplored. We describe a unified strategy for constructing carbon, boron, and germanium-centered chiral spirocyclic skeletons via enantioselective hetero [2+2+2] cycloaddition of a bis-alkyne with a nitrile. A chiral designer Ni(0)NHC complex enables the required long-range enantioinduction. The resulting enantio-enriched spirocycles feature a pyridine motif, making them exploitable for ligand design and functional materials featuring attractive photophysical and chiroptical properties.