Enantioselective synthesis of C2-symmetric spirobipyridine ligands through cationic Rh(I)/modified-BINAP-catalyzed double [2+2+2] cycloaddition

Enantioenriched C-2-symmetric spirobipyridine ligands were efficiently synthesized through a cationic rhodium(I)/(R)-Segphos or (R)-H-8-BINAP complex-catalyzed enantioselective intramolecular double [2 + 2 + 2] cycloaddition of bis-diynenitriles.