Chiral Atropisomeric-NHC Catechodithiolate Ruthenium Complexes for Z-Selective Asymmetric Ring-Opening Cross Metathesis of Exo-Norbornenes

A set of 16 chiral ruthenium complexes containing atropisomerically stable N-Heterocyclic Carbene (NHC) ligands was synthesized from prochiral NHC precursors. After a rapid screening in asymmetric ring-opening-cross metathesis (AROCM), the most effective chiral (atrop)BIAN-NHC Ru-catalyst (up to 97 : 3 er) was then converted to a Z-selective catechodithiolate complex. The latter proved to be highly efficient in Z-selective AROCM of exo-norbornenes affording valuable trans-cyclopentanes with excellent Z-selectivity (>98 %) and high enantioselectivity (up to 96.5 : 3.5 er).

Automated summary

A set of 16 chiral ruthenium complexes with atropisomerically stable N-Heterocyclic Carbene (NHC) ligands were synthesized. Among them, (atrop)BIAN-NHC Ru-catalyst showed the highest activity (up to 97 : 3 enantiomeric ratio) in asymmetric ring-opening-cross metathesis (AROCM) and was further converted to a Z-selective catechodithiolate complex. This complex exhibited high efficiency in Z-selective AROCM of exo-norbornenes, producing trans-cyclopentanes with excellent Z-selectivity (>98%) and high enantioselectivity (up to 96.5 : 3.5 enantiomeric ratio).