Oxidative coupling polymerization of racemic 3,3 '-dihydroxy-2,2 '-dimethoxy-1,1 '-binaphthalene with copper(II)-(-)-sparteine complex

摘要

The oxidative coupling polymerization of racemic 3,3'-dihydroxy-2,2'-dimethoxy-1,1'-binaphthalene with copper(II) chloride-(-)-sparteine [(-)Sp] in methanol at room temperature was carried out and the enantiomer-selectivity during the polymerization was examined. The (R)-monomer preferentially reacted, and the purity of the unreacted monomer reached 80%ee (S) after 15 h, while that of the polymerized monomer gradually decreased from 26%ee (R) as a function of the polymerization. The ratio of the rate constants of both enantiomers, s=k(R)/k(S), was determined to be 2.3. The model coupling reaction of the mono-benzylated (R)-monomer with CuCl2-(-)Sp showed that the R-configuration with respect to the carbon-carbon bonds between the monomer units was selectively constructed during the polymerization.