Bismuth(III)-catalyzed dehydrative etherification and thioetherification of phenolic hydroxy groups

Reduced Phenalenyl in Catalytic Dehalogenative Deuteration and Hydrodehalogenation of Aryl Halides

Dehalogenative deuteration reactions are generally performed through metal-mediated processes. This report demonstrates a mild protocol for hydrodehalogenation and dehalogenative deuteration of aryl/heteroaryl halides (39 examples) using a reduced odd alternant hydrocarbon phenalenyl under transition metal-free conditions and has been employed successfully for the incorporation of deuterium in various biologically active compounds. The combined approach of experimental and theoretical studies revealed a single electron transfer-based mechanism.

Bsi(OTf)3-mediated tandem annulation of 1-aryl isochroman-3-ones with oxygenated arenes: one-pot synthesis of polyoxygenated homotriptycenes

Bi(OTf)3 (bismuth triflate)-mediated one-pot tandem annulation of oxygenated 1-aryl isochroman-3-ones with oxygenated arenes provides polyoxygenated homotriptycenes in moderate to good yields in MeNO2 at reflux (101 °C) for 10 h under an air atmosphere and easy-operational conditions via intermolecular and intramolecular Friedel-Crafts type procedures. A plausible mechanism is proposed and discussed. This protocol provides a highly effective ring-closure via three carbon-carbon (C-C) bond formations.

Benzannulation of isobenzopyryliums with electron-rich alkynes: a modular access to β-functionalized naphthalenes

Described here is a modular strategy for the rapid synthesis of β-functionalized electron-rich naphthalenes, a family of valuable molecules lacking general access previously. Our approach employs an intermolecular benzannulation of in situ generated isobenzopyrylium ions with various electron-rich alkynes, which were not well utilized for this type of reaction before. These reactions not only feature a broad scope, complete regioselectivity, and mild conditions, but also exhibit unusual product divergence depending on the substrate substitution pattern. This divergence allows further expansion of the product diversity. Control experiments provided preliminary insights into the reaction mechanism.

A substituent-controlled divergent benzannulation provides rapid access to various β-functionalized naphthalenes from electron-rich alkynes.

Acid-catalyzed synthesis of condensed polycyclic diaryl ethers from arenols

Diaryl ethers containing condensed polycyclic aryl groups were synthesized from arenols in the presence of a catalytic amount of p-chlorobenzenesulfonic acid. Symmetrical binaphthyl, biphenanthryl, and bipyrenyl ethers were obtained in high yields. Unsymmetrical derivatives were also synthesized from 9-phenanthrol and arenols, using combinations of reactive and unreactive substrates.

Brønsted Acid Catalyzed Functionalization of Aromatic Alcohols through Nucleophilic Substitution of Hydroxyl Group

The hydroxyl groups of naphthol and tautomerizable phenol derivatives have been substituted by O-, S-, N-, and C-centered nucleophiles under solvent-free reaction conditions. The products are generated in good to excellent yields. para-Toluenesulfonic acid exhibits the best catalytic activity compared to other Brønsted acids. Experimental observations suggest that the reaction proceeds through the intermediacy of the keto tautomer of naphthol. Nucleophilic addition to the carbonyl group followed by elimination of water generates the desired product. The present methodology provides access to substituted naphtho[2,1-b]furan derivatives. The products generated using N-centered nucleophiles can be further transformed to important classes of organic molecules such as benzocarbazole and imidazole derivatives.

Bismuth(iii) triflate-catalysed tandem cyclisations towards complex polycyclic ethers

A series of complex polycyclic ethers have been synthesised under very mild conditions using a low catalyst loading of bismuth(iii) triflate.

1,3-Dicyclohexylimidazol-2-ylidene as a superior ligand for the nickel-catalyzed cross-couplings of aryl and benzyl methyl ethers with organoboron reagents

A new catalytic system has been developed involving the use of Ni(cod)2 in conjunction with 1,3-dicyclohexylimidazol-2-ylidene for the cross-coupling of aryl and benzyl methyl ethers with organoboron reagents. This method not only allows for the use of readily available methyl ethers as halide surrogates but also provides a functional group tolerant method for the late-stage derivatization of complex molecules.