Oxidative Coupling Of 2-naphthol Derivatives Research Articles

An enantioselective oxidative coupling reaction of 2-naphthol derivatives catalyzed by chiral diphosphine oxide-iron(ii) complexes.

An enantioselective oxidative coupling of 2-naphthol derivatives is developed with the use of chiral Fe(ii)-diphosphine oxide complexes. Optically active 1,1-bi-2-naphthol derivatives can be synthesized in high yields when a 2 : 1 complex of (S)-xylyl-iPrO-BIPHEP-oxide and Fe(OTf)2 is used in the presence of t-butyl hydroperoxide as an oxidant. The non-linear effect, X-ray crystal structure and ESI-MS suggest that a 2 : 1 complex of (S)-xylyl-iPrO-BIPHEP-oxide and Fe(OTf)2 is a pre-catalyst for a Fe(iii)/Fe(iv) redox cycle.

Reversal of Enantioselectivity Approach to BINOLs via Single and Dual 2-Naphthol Activation Modes.

A mechanism-driven enantiodivergent approach to chiral 1,1'-bi-2-naphthols via catalytic asymmetric oxidative coupling of 2-naphthol derivatives is described for the first time. By utilizing 2-naphthol derivatives with low oxidation potential, the substrates were activated by either chiral mononuclear or dinuclear vanadium(V) catalyst to promote distinctively different asymmetric reaction pathways: single versus dual substrate activation mechanisms.

Enantioselective and aerobic oxidative coupling of 2-naphthol derivatives using chiral dinuclear vanadium(V) complex in water

The enantioselective oxidative coupling of 2-naphthols in water was established using dinuclear vanadium(V/IV) catalysis with O2 as the sole co-oxidant. In the vanadium-catalyzed reaction, the corresponding coupling products were obtained in good to excellent yields with up to 94% enantiomeric excess. In water, racemization of the coupling product was suppressed even at high temperature (70°C).

Aerobic Oxidative Coupling of 2-Naphthol Derivatives Catalyzed by a Hexanuclear Bis(μ-hydroxo)copper(II) Catalyst

A novel hexanuclear bis(μ-hydroxo)copper(II) complex, [L3(Cu2(μ-OH)2)3](ClO4)6 (1), was synthesized with dinucleating ligand N,N,N,N-tetra(pyridin-2-ylmethyl)-m-xylene diamine (L). Complex 1 is fully characterized by X-ray crystallography and magnetic susceptibility in the solid state and UV–vis and electron paramagnetic resonance spectroscopy in solution. The molecular structure of 1 possesses three dicopper cores, in which two copper centers are bridged by two hydroxide groups and separated by a distance ranging from 2.8852(15) to 2.8937(10) Å. In addition, the three dicopper cores are linked by the dinucleating ligand between each pair of adjacent dicopper cores. Importantly, aerobic oxidative coupling of 2,4-di-tert-butylphenol, 2-naphthol, and six 2-naphthol derivatives was achieved in 33–96% yield using complex 1 as a catalyst.

One-Pot Preparation of Chiral Dinuclear Vanadium(V) Complex

A convenient one-pot procedure for the preparation of dinuclear vanadium(V) complex is described. The complex exhibited high catalytic activity for oxidative coupling of 2-naphthol derivatives. In addition, coupling of 9-phenanthrol gave (S)-10,10′-dihydroxy-9,9′-biphenanthryl in quantitative yield with 93% ee.

Iron-Catalyzed Asymmetric Aerobic Oxidation: Oxidative Coupling of 2-Naphthols

Fe(salan) complexes were found to be efficient catalysts for the asymmetric aerobic oxidative coupling of 2-naphthol derivatives. This reaction can be carried out in air at 60 degrees C with high enantioselectivity up to 97% ee. This is the first report for asymmetric aerobic oxidation using molecular oxygen in air in the absence of additives.

Dual activation in oxidative coupling of 2-naphthols catalyzed by chiral dinuclear vanadium complexes

An efficient enantioselective oxidative coupling of 2-naphthol derivatives based on a concept of dual activation catalysis is realized. A chiral dinuclear vanadium(IV) complex ( R a, S, S)- 1e possessing ( S)- tert-leucine moieties at the 3,3′-positions of the ( R)-binaphthyl skeleton was developed, which was found to promote the oxidative coupling of 2-naphthol to afford ( S)-BINOL with 91% ee. To verify the dual activation mechanism, mononuclear vanadium(IV) complex ( S)- 8 was also prepared. Kinetic analysis revealed that the reaction rate of oxidative coupling of 2-naphthol promoted by ( R a, S, S)- 1e is 48.3 times faster than that of ( S)- 8. The two vanadium metals in the chiral complex activate two molecules of 2-naphthol simultaneously in an intramolecular manner coupling reaction, achieving a high reaction rate with high enantiocontrol. Reaction mechanisms of the oxidative coupling reaction promoted by either vanadium(IV) or vanadium(V) complexes are also described.

Enantioselective oxidative coupling of 2-naphthol derivatives catalyzed by Camellia sinensis cell culture

Optically active 1,1′-binaphthyl-2,2′-diols were synthesized by oxidative coupling of 2-naphthols using Camellia sinensis cell culture as a catalytic system.

Synthesis and application of novel biaryl compounds with axial chirality as catalysts in enantioselective reactions

A highly efficient process of aerobic oxidative coupling of 2-naphthol derivatives catalyzed by Cu(OH)Cl.TMEDA has been developed. Enantioselective oxidative coupling of 2-naphthol derivatives was achieved by the use of a chiral catalyst prepared from proline-derived diamine and cuprous chloride, affording the corresponding BINOL derivatives in good enantioselectivities of up to 78% ee. A new catalytic, enantioselective allylation of aldehydes with allyltrichlorosilanes exploiting (S)-3,3'-dimethyl-2,2'-biquinoline N,N'-dioxide as a catalyst affords homoallylic alcohols in virtually complete diastereoselectivities and high enantioselectivities of up to 92% ee, wherein the use of diisopropylethylamine as an additive has proven to be crucial for the acceleration of the catalytic cycle. It is also noteworthy that the above finding represents the first successful example of asymmetric reactions utilizing amine N-oxide as a chiral catalyst.

Enantioselective Synthesis of Binaphthol Derivatives by Oxidative Coupling of Naphthol Derivatives Catalyzed by Chiral Diamine·Copper Complexes

A highly efficient process of aerobic oxidative coupling of 2-naphthol derivatives catalyzed by 1 mol % of Cu(OH)Cl·TMEDA has been developed. Enantioselective oxidative coupling of naphthols was achieved by the use of 10 mol % of chiral catalysts prepared from proline-derived diamines and cuprous chloride, affording the corresponding binaphthols in good enantioselectivities of up to 78% ee. The ester moiety at the 3-position of the substrate was found to be essential for the good asymmetric induction observed in the present coupling reaction.

Aerobic Oxidative Coupling of 2-Naphthol Derivatives Catalyzed by a Copper-Amine Complex without Solvent.

Aerobic oxidative coupling of naphthols catalyzed by a copper-amine complex was found to proceed without solvent in high efficacy. The present reaction was applied to a practical synthesis of 1, 1'-binaphthalene-2, 2'-diol on multi-gram scale.

A new catalytic system for aerobic oxidative coupling of 2-naphthol derivatives by the use of CuCl-amine complex: a practical synthesis of binaphthol derivatives

A new catalytic system for aerobic oxidative coupling of 2-naphthol derivatives by the use of CuCl-amine complex: a practical synthesis of binaphthol derivatives

A new catalytic system for aerobic oxidative coupling of 2-naphthol derivatives by the use of CuCl-amine complex: A practical synthesis of binaphthol derivatives

Aerobic oxidative coupling of 2-naphthol derivatives by the use of 1 mol% of CuCl-amine complex afforded binaphthol derivatives in excellent yields.