The Asymmetric Ullmann Coupling Reaction of (S)-2,2'-Bis(1-bromo-2-naphthoyloxy)-1,1'-binaphtyl Revisited. Formation of 24-Membered Optically Pure Cyclic Dimer as Well as 12-Membered Cyclic Monomer

Article abstract of DOI:10.1246/bcsj.59.235

The copper-promoted Ullmann reaction of the title diester proceeded with high stereoselectivity to give 24-membered optically pure cyclic dimer of (S,S,S,S)-configuration as well as 12-membered monomeric cycle of (S,S)-configuration.The reaction also gave reduced, open-chain dimer enriched in (S,R,S)-diastereomer(S,S,S)-counterpart (17percent d.e.).Stereochemical course to the cyclic dimer was discussed considering the result that the intermolecular Ullmann coupling of chiral alcohol esters of 1-bromo-2-naphthoic acid poorly induced axial chirality in the joining of the two naphthyl units.