Practical synthesis of axially chiral dicarboxylates via Pd-catalyzed external-CO-free carbonylation

Abstract

We have developed a safe and practical synthetic method for preparing axially chiral diphenyl dicarboxylates using Pd- catalyzed external-CO-free carbonylation with phenyl formate as a CO surrogate. Optimized conditions consisted of axially chiral [1,1′-binaphthalene]-2,2′-diyl ditriflate and its congeners, each easily prepared from commercially available enantiomerically pure diols, Pd(OAc)2, 1,3-bis(diphenylphosphino)-propane, ethyldiisopropylamine, and no solvent. To demonstrate the potential utility of these products, this method was conducted on gram-scale and the phenyl ester products were converted to other useful compounds, and both processes were carried out without difficulty.