Diastereoselective synthesis of C2-symmetric hexacoordinated phosphate anions (HYPHATs) with predetermined chirality from 1,2-diaryl-ethane-1,2-diols

C2-symmetric HYPHAT anion (5) made of a central phosphorus(V) atom, one hydrobenzoin and two tetracholorocatechol ligands can be simply prepared in high yield as its dimethylammonium salt using a one pot-process and simple commercially available or easily prepared starting materials. The presence of the chiral hydrobenzoin ligands (e.g. R,R) leads to the formation of diastereomeric anions (Δ,R,R/Λ,R,R). A partial control over the configuration of the adduct by the chiral ligands is observed (diastereomeric ratio (d.r.) 75:25 in 5% DMSO–CHCl3). This asymmetric induction can be improved (d.r. up to 90:10) by the introduction of ortho bromo substituents on the phenyl rings of the 1,2-diaryl-ethane-1,2-diol ligands.