The Asymmetric Ullmann Coupling Reaction of Chiral Diol Diesters of 1-Bromo-2-naphthoic Acid and 2-Halo-3-nitrobenzoic Acids: Highly Diastereoselective Synthesis of Atropisomeric 6,6'-Dinitrodiphenic Acids

Article abstract of DOI:10.1246/bcsj.57.1943

The copper-promoted Ullmann reaction of chiral diol diesters of 1-bromo-2-naphthoic acid induced axial dissymmetry into the newly formed 1,1'-binaphthyl bond: chiral diol, apparent net optical yield for the joining of two napphthyl units, and axial chirality induced are as follows: (S)-1,1'-binaphthyl-2,2'-diol, 71percent, S; (1S,2S)-1,2-diphenyl-1,2-ethanediol. 32percent, S; (1R,2R)-1,2-bis(ethoxycarbonyl)-1,2-ethanediol. 33percent.S; (4S,5S)-bis(hydroxymethyl)-2,2-dimethyl-1,3-dioxolane, 3.7percent, R.The reaction of (R)-1,1'-binaphthyl-2,2'-diol esters of 2-halo-3-nitrobenzoic acid gave up to 85percent net optical yield for the c oupling; the intramolecular cyclization proceeded with virtually complete diastereoselectivity to give cyclic diester of R,R-configuration in a 42percent isolated yield.This remarkable stereocontrol is ascribed to the steric requirement of the 12-membered cyclic diester structure containing rigid 1,1'-binaphthyl and 1,1'-biphenyl moiety.