Highly Efficient and Practical Optical Resolution of 2-Amino-2'-hydroxy-1, 1'-binaphthyl by Molecular Complexation with N-Benzylcinchonidium Chloride: A Direct Transformation to Binaphthyl Amino Phosphine

摘要

A new type of N, P chiral ligand, binaphthyl amino phosphine 1 was synthesized through a simple and practical resolution of racemic 2-amino-2'-hydroxy-1, 1'-binaphthyl by molecular complexation with 0.5 equivalents of N-benzylcinchonidium chloride in the solid state. The present procedure represents the first example of the optical resolution of amino alcohol with the use of a chiral ammonium salt as a resolving reagent. The resolution mechanism is discussed in terms of molecular recognition in solid state. The chlorine anion in N-benzylcinchonidium chloride provides the bridging link between two amino alcohol molecules [(+)-2] and the cinchonoid cation located in between, by hydrogen bonding with the surrounding moieties.