Synthesis And Characterization Of Novel Binaphthol Complexes

The synthesis of chiral compounds is one of the most attractive fields in organic synthesis, and chiral catalysts play a very important role in the synthesis. Chiral 1,1'-bi-2-binaphthol (BINOL) is one of the most prominent C2 axial-chiral ligands, although it don't have chiral center. The chrial ligands and chrial catalysts synthesized from BINOL play a very important role in the asymmetric synthesis. In this paper we synthesized some new BINOL ligands:2,2'-bialkoxy-1,1'-binaphthyl-3,3'-dicaboxylic aicd, and eleven coordination complexes.Using FeCl3·6H2O as catalyst, BINOL-3,3'-dicaboxylic acid (2) was prepared from 3-hydroxy-2-naphthoic acid (1) by oxidative coupling under microwave irradiation, with 74.0% yield. Methyl,ethyl,butyl and benzyl ether of BINOL-3,3'-dicaboxylic acid (4a-4d) is obtained via esterification, etherification and saponification to protect the hydroxyl groups, the overall yield is 45.2%,52.3%,44.7%和42.8%, respectively.Single crystals of BINOL-3,3'-dicaboxylic acid (2) coordinatied with Co(Ⅱ),Mn(Ⅱ),Pb(Ⅱ) was obtained by solution diffusion. The structure of Co(BIONLDC)(DMF)2(H2O)2]n·nDMSO (5, BINOLDC=BINOL-3,3'-dicaboxylate) was detemined by single crystal X-ray diffraction. The single crystal X-ray diffraction analysis reveals that complex includes a mononuclear complex and a non-coordinated DMSO molecular, the ligands including BINOL-3,3'-dicaboxylic acid (2),DMF and H2O molecular. The Co(Ⅱ) is hexa-coordinated and the local geometry around it can be described as a distorted octahedron. The mononuclear molecules are connected by hydrogen bonds to form a supramolecular.By solution diffusion, we also obtained complex single crystals of 2,2'-dimethoxy-1,1'-binaphthyl-3,3'-dicaboxylic acid (4a) with Pd(Ⅱ),Cd(Ⅱ),Zn(Ⅱ); 2,2'-diethoxy-1,1'-binaph thyl-3,3'-dicaboxylic acid (4b) with Pd(Ⅱ) and 2,2'-dibenzyloxy-1,1'-binaphthyl-3,3'-dicabo xylic acid (4d) with Co(Ⅱ),Zn(Ⅱ).