Triethylammonium 1,1′-binaphthyl-2,2′-diyl phosphate

In the crystal structure of the title compound, C6H16N+·C20H12O4P−, an N—H⋯O interaction links the cation to the anion. The N atom in the triethylammonium cation exhibits a trigonal-bipyramidal coordination geometry and forms an N—H⋯O interaction with one phosphate O atom of the 1,1′-binaphthyl-2,2′-diyl phosphate ligand. A bifurcated C—H⋯O interaction with the other phosphate O atom links molecules along the a axis. The dihedral angle between the two naphthyl ring systems is 58.92 (3)°. The refined Flack parameter value of 0.50 (10) indicates inversion twinning.

In the crystal structure of the title compound, C 6 H 16 N + Á-C 20 H 12 O 4 P À , an N-HÁ Á ÁO interaction links the cation to the anion. The N atom in the triethylammonium cation exhibits a trigonal-bipyramidal coordination geometry and forms an N-HÁ Á ÁO interaction with one phosphate O atom of the 1,1 0binaphthyl-2,2 0 -diyl phosphate ligand. A bifurcated C-HÁ Á ÁO interaction with the other phosphate O atom links molecules along the a axis. The dihedral angle between the two naphthyl ring systems is 58.92 (3) . The refined Flack parameter value of 0.50 (10) indicates inversion twinning.

Comment
The title compound is a salt of binol phosphoric acid. It represents a useful tool for the resolution of amines. Amines which are unable to resolve using other chiral acids, are resolved using binolphosphoric acid very easily and in high yield (Jacques et al., 1971). Optically active amines are useful as intermediates of medicines, agricultural chemicals, or the like can be produced without special post-treatment in high yield at high optical purity using optically active phosphoric acid derivatives. A recent report depicts phosphoric acid acts as Bronsted acid to catalyze the addition of enolizable β-diketones, β-ketoesters, and vinylogous amides to α,β-unsaturated aldehydes to lead to substituted chromenones, pyranones, and tetra  (Table 1) along the a axis extending into a network ( Figure 2). The molecular structure viewed down along the C10-C11 pivot, clearly shows the non co-planar geometry of the two naptha rings system with a dihedral angle of 58.92 (3)°.

Experimental
To a stirred ice cold solution of 0.2 g (0.69 mole) binol (Evan et. al, 1977) in 20 mL of dichloromethane under nitrogen atmosphere was added 0.07 mL (0.69 mmol) POCl 3 drop wise followed by addition of 0.5 mL (3.5 mmol) triethylamine.
White fumes of HCl were observed upon addition, reaction mixture was stirred at 0 °C for 30 minutes. Then 0.13 mL (6.9 mmol) H 2 O was added slowly at 0 °C. Reaction mixture was stirred at 0 °C for 1 h and warmed up to room temperature and stirred for 40 h. The reaction was monitored using thin layer chromatography. The product was extracted using dichloromethane and purified by crystallization in dichloromethane. Yield is found to be 0.26 g (83.9 %).

Refinement
All hydrogen atoms were fixed geometrically and allowed to ride on the parent carbon atoms with aromatic C-H = 0.93 Å, aliphatic C-H = 0.98 Å and methyl C-H = 0.96 Å. The displacement parameters were set for phenyl and aliphatic H atoms at U iso (H) = 1.2U eq (C) and for methyl H atoms at U iso (H) = 1.5U eq (C). The Flack parameter was refined as a full least-squares variable, and the refined value of 0.50 (10) suggests inversion twinning.  supplementary materials sup-9