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

Abstract

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 O2 atmosphere. For example, a 10/1 (v/v) MeOH · H2O‐insoluble polymer with a number‐average molecular weight of 3.8 × 103, 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. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4528–4534, 2004

Synthesis of Poly(binaphthol) via Controlled Oxidative Coupling

“…The OCP of rac-HMBN with a dinuclear-type copper catalyst in CH 2 Cl 2 -methanol (7/1 (v/v)) at room temperature was also examined (Scheme 11.13). The 2CuCl-BMX complex produced a polymer with an M n of 3.3 × 10 3 (M w /M n = 5.1) in 65% yield after acetylation of the hydroxyl groups, similar to the results reported for the conventional Cu(I)-diamine reagents [26][27][28][29]. Polymerization with a copper(II) catalyst (2CuCl 2 -BMX), however, resulted in a much lower yield (28%, M n = 2.3 × 10 3 , M w /M n = 1.4).…”

“…On the other hand, the asymmetric OCP of 2,3-DHN with the CuCl-(+)-1-(2-pyrrolidinylmethyl)pyrrolidine [(+)PMP] and CuCl 2 -(−)-sparteine [(−)Sp] complexes (Scheme 11.12), which are well known as effective reagents for the oxidative coupling reaction that produces the 1,1 -bi-2-naphthol derivatives [9,25], could not produce a polymer [5,26], although the poly(2,3-DHN) derivative was obtainable by the OCP with these conventional reagents using 3,3 -dihydroxy-2,2 -dimethoxy-1,1 -binaphthalene (HMBN) as the monomer (Scheme 11.13) [26][27][28][29].…”

Oxidative coupling polymerization of octahydroxyquaternaphthyl derivatives producing stereocontrolled polybinaphthol

“…The obtained methanol-insoluble polymers from the quaternaphthyls showed an M n value around 4−5 x 10 3 , therefore, these are the oligomers with approximately 5−6 monomer units, which correspond to about 20 repeating units with respect to the naphthalene. In previous studies, the stereochemistry of the bond newly formed during the polymerization (R : S) can be estimated from the methyl carbon absorption of the acetyl groups in the 13 C NMR spectrum for the polymer obtained from the optically active monomers [10,12]. Figure 2 shows the 13 C NMR spectrum of poly-(SSS)-2' obtained using the CuCl-(S)Phbox catalyst (run 4), and the peaks are assigned as shown in the figure, based on the fact that (SSS)-2 was used as a monomer.…”

“…The 1 H and 13 C NMR spectra were measured using a Varian Unity-Inova spectrometer (500 MHz for 1 H) in CDCl 3 . The infrared (IR) spectra were recorded by a Horiba FT-720 spectrometer.…”

Molecular Oxygen Binding and Activation: Oxidation Catalysis

“…Palladium-catalyzed oxidations are not the only systems to benefit from the use of amine ligands, as copper systems have also utilized diamine ligands for direct O 2 -coupled aerobic oxidations. As an example, (-)-Phbox, and (+)-PMP ligands have been successfully used in an asymmetric copper coupling of 1,1'-bi-2-naphthol units (Scheme 5.19) [67]. Very recently Porco and coworkers reported a Cu(I)/(-)-sparteine-mediated system for the enantioselective oxidative dearomatization of catechols with up to 97% ee (Scheme 5.20) [68].…”