Asymmetric synthesis of axially chiral 1,1′-biphenyl-2-carboxylates via nucleophilic aromatic substitution on 2-menthoxybenzoates by aryl Grignard reagents
Abstract
A practical method is presented for an asymmetric synthesis of axially chiral 1,1′-biphenyl-2-carboxylates via the ester-assisted nucleophilic aromatic substitution reaction. Thus, upon treatment of 2-tert-butylphenyl 2-[(–)-menthoxy]benzoates with an aryl Grignard reagent, chirality of the leaving (–)-menthoxy group is transferred to the newly formed biphenyl linkage with up to 94% optical yield.