Novel chiral C₁-1′,2′,3′,4′-tetrahydro-1,1′- bisisoquinolines: synthesis, resolution, and applications in catalytic enantioselective reactions

A straightforward synthesis of a structurally constrained C₁-1′,2′,3′,4′-tetrahydro-1,1′- bisisoquinoline 1 is described. Resolution of this compound has been achieved successfully. The preparation of chiral N-alkyl, urea, and thiourea derivatives as potential new chiral ligands, based on the parent compound 1, is reported. Chiral compound 1 induced very good selectivity and yield in the addition of either Et₂Zn (85% ee, 96% yield) or nitromethane (85% ee, 60% yield) to benzaldehyde.