Design of C2-symmetric tetrahydropentalenes as new chiral diene ligands for highly enantioselective Rh-catalyzed arylation of N-tosylarylimines with arylboronic acids

A new type of C-2-symmetric chiral diene ligand bearing a simple bicyclic [3.3.0] backbone was discovered. (3aS,6aS)-3,6-diphenyl-1,3a,4,6a-tetrahydropentalene was applied successfully in the Rh-catalyzed asymmetric arylation of N-tosylarylimines with arylboronic acids. With the new chiral diene ligand, a broad range of highly enantiomerically enriched diarylmethylamines (98-99% ee) as well as 3-aryl substituted phthalimidines (99% ee) could be easily prepared.