Varela, Jesús A. Castedo, Luis Saá, Carlos One-Step Synthesis of Spiropyridines, a Novel Class of <i>C</i><sub>2</sub>-Symmetric Chiral Ligands, by Cobalt(I)-Catalyzed [2 + 2 + 2] Cycloadditions between Bis-Alkynenitriles and Alkynes<sup>†</sup> Spiropyridines, a novel series of <i>C</i><sub>2</sub>-symmetric ligands, can be obtained in moderate yields by means of Co(I)-catalyzed double cocyclization between bis-alkynenitriles and alkynes. This one-step method allowed the first synthesis of the interesting 7,7‘- and 8,8‘-spyropyridines from acyclic precursors. cocyclization;C 2;alkyne;synthesis;method;series;Synthesi;Spiropyridine;Alkyne;spyropyridine;Co;acyclic;precursor;ligand;yield;Cobalt;Cycloaddition;Symmetric Chiral Ligands 1999-12-09
    https://acs.figshare.com/articles/journal_contribution/One-Step_Synthesis_of_Spiropyridines_a_Novel_Class_of_i_C_i_sub_2_sub_-Symmetric_Chiral_Ligands_by_Cobalt_I_-Catalyzed_2_2_2_Cycloadditions_between_Bis-Alkynenitriles_and_Alkynes_sup_sup_/3761364
10.1021/ol991195m.s001