Synthesis And Resolution Of NOBIN

Axial chirality was very important in chiral synthesis because of its rigidity and flexibility. In terms of ligand symmetry, C2- symme trical ligands possessing axial chirality have found particularly wide utility in asymmetric catalysis. Since 1990 the 2,2'-Disubstituted de rivatives of optically active 1,1'-binaphthyl have been widely used in organic synthesis as ligands and small molecule catalysts. Their representa tives are 1,1'-bi-2-naphthol(BINOL), 2,2'-diamine-1,1'- binaphthyl (BINAM),2- amino-2'-hydroxy-1, 1-binaphthyl(NOBIN) and 2- amino–2'-thiol- 1,1-binaphthyl.We synthesized 2- amino-2'-hydroxy-1,1-binaphthyl(NOBIN) by oxida tion -coupling through Cu(Ⅱ). During the synthesis process, the effect of amount of solvent and temperature on product yield was studied. By means of reducing the amount of solvent, the production yield was increased to 70 % from 62 % which reported by literature. So that the amount of waste residue was reduced and the environment pollution weakened.We developed a new way to resolute NOBIN, ee was up to 100%. The measures used to resolute NOBIN either had a low yield and low ee or needed expensive resolution reagents. Based on lots of literatures, we adopted L-proline as resolution reagent which is cheap and plentiful. The L-proline protected by Cbz reacted with NOBIN to make acid amide. Later, (R,S)-Cbz-proline-2-carboxylic acid–NOBIN-amide and (S,S)-Cbz-proline-2-carboxylic acid–NOBIN-amide were respectively obtained by silica gel column. During the hydrolysis process of acid amide, difficulty appeared. Under base condition, the result of hydrolysis was very disappointed; under acid condition, optically active NOBIN was obtained, ee was up to 100%. Both temperature and solvent had great influence on ee under acid condition. When toluene was used as solvent, the ee would decline remarkable once temperature exceeded 60℃; when ethanol was used as solvent, a interesting phenomenon appeared: the configuration of NOBIN obtained from hydrolysis had partially tumbled.