title: Enantioselective oxidative biaryl coupling reactions catalyzed by 1,5-diazadecalin metal complexes: efficient formation of chiral functionalized BINOL derivatives.
abstract: Chiral 1,5-diaza-cis-decalins have been examined as ligands in the enantioselective oxidative biaryl coupling of substituted 2-naphthol derivatives. Under the optimal conditions employing 2.5-10 mol % of a 1,5-diaza-cis-decalin copper(II) catalyst with oxygen as the oxidant, enantioselective couplings (44-96% ee) could be achieved for a range of 3-substituted 2-naphthols including the ester, ketone, phosphonyl, and sulfonyl derivatives. The relationship between the substitution of the naphthalene starting materials and reactivity/selectivity is determined by several factors which act in concert: (1) the effect of substituents on the oxidation potential of the substrate, (2) the ability of the substrate to participate in a chelated copper complex which depends on (a) the inherent coordinating ability of the 3-substituent and (b) substituent steric interactions that affect chelation between the 2-hydroxyl and 3-substituent, (3) the effect of substituents on dissociation of the product from the copper catalyst.
authors.affiliation: Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Li
authors.forename: J Brian
authors.initials: JB
authors.lastname: Hewgley
authors.forename: Carol A
authors.initials: CA
authors.lastname: Mulrooney
authors.forename: Jaemoon
authors.initials: J
authors.lastname: Yang
authors.forename: Marisa C
authors.initials: MC
authors.lastname: Kozlowski