Asymmetric oxidative coupling polymerization affording polynaphthylene with 1,1′‐bi‐2‐naphthol units

The oxidative coupling polymerizations of racemic‐, ( R )‐, and ( S )‐2,2′‐dimethoxymethoxy‐1,1′‐binaphthalene‐3,3′‐diols were carried out with a copper catalyst with various ligands, such as N,N,N ′ ,N ′‐tetramethylethylenediamine (TMEDA), ( S )‐(+)‐1‐(2‐pyrrolidinylmethyl)pyrrolidine, (−)‐sparteine, and ( S )‐(−)‐2,2′‐isopropylidenebis(4‐phenyl‐2‐oxazoline) [(−)‐Phbox], under an O 2 atmosphere. For example, a 10/1 (v/v) MeOH · H 2 O‐insoluble polymer with a number‐average molecular weight of 3.8 × 10 3 , from a polymerization with CuCl–TMEDA followed by acetylation of the hydroxyl groups, was obtained in a 71% yield. Polymerization with (−)‐Phbox proceeded in an S ‐selective manner to give a polymer with the highest negative specific rotation from the ( S )‐monomer. The obtained polymer was successfully converted into a polymer with the optically pure 1,1′‐bi‐2‐naphthol unit based on the original monomer structure, which could be used as a polymeric chiral auxiliary and showed catalytic activity for the asymmetric diethylzinc addition reaction to aldehydes.