10.1039/c7ob02882b
The study explores the use of bis-(amino)cyclopropenylidene (BAC) as a non-covalent Br?nsted base catalyst in conjugate addition reactions, specifically in 1,4- and 1,6-conjugate additions of carbon nucleophiles to enones and p-quinone methides (p-QMs). The chemicals used in the study include a range of p-QMs, carbon nucleophiles such as diethyl malonate and 2-naphthols, and BAC as the catalyst. The purpose of these chemicals was to investigate the efficiency of BAC in facilitating the formation of unsymmetrical diaryl- and triarylmethanes, which are important in synthetic chemistry. The study demonstrated that BAC could effectively catalyze these reactions under mild conditions, yielding the desired products in good to excellent yields, thus providing a straightforward access to a variety of diaryl and triarylmethanes.
10.1021/jo00075a045
This research delves into the decomposition reactions of o-alkynyl or o-alkenyl α-diazoaceto- and propiophenone derivatives under various conditions, including photochemical, thermal, and rhodium-catalyzed processes. The study's purpose is to understand how the reaction outcomes are markedly dependent on the nitrogen extrusion conditions. The chemicals used in the process include o-alkynyl α-diazopropiophenone derivatives, which upon thermolysis or photolysis yield polysubstituted β-naphthols through Wolff rearrangement and intramolecular cyclization. In contrast, Rh(II)-catalyzed decomposition leads to a different set of products, involving the formation of vinyl carbenoid intermediates and subsequent reactions.
10.3184/174751911X13230223609418
The research explores a novel and efficient method for synthesizing benzo[a]xanthene-11-one derivatives, which are important heterocycles known for their antiviral, anti-inflammatory, and antibacterial properties. The study aims to develop a green and rapid synthesis route using nanoparticle silica supported sulfuric acid (NPs SiO2-H2SO4) as a solid phase acidic catalyst. 2-naphthol plays a crucial role as one of the key reactants in the synthesis process. Specifically, 2-naphthol is used in conjunction with aromatic aldehydes and dimedone to form benzo[a]xanthene-11-one derivatives through a three-component condensation reaction catalyzed by nanoparticle silica supported sulfuric acid (NPs SiO2-H2SO4). This reaction is carried out in CH2Cl2 solvent at room temperature, yielding the desired products in high yields. The use of 2-naphthol is essential for the formation of the benzo[a]xanthene-11-one core structure, contributing to the development of compounds with significant biological activities, such as antiviral, anti-inflammatory, and antibacterial properties.
10.1039/c9cc07834g
Takahiro Horibe et al. present a method for synthesizing optically active 1,1-bi-2-naphthol derivatives (BINOLs) using chiral Fe(II)–diphosphine oxide complexes. The study focuses on the enantioselective oxidative coupling of 2-naphthol derivatives, which is a straightforward method for constructing chiral BINOLs. The researchers found that a 2:1 complex of (S)-xylyl-iPrO-BIPHEP-oxide and Fe(OTf)2, in the presence of t-butyl hydroperoxide as an oxidant, effectively catalyzed the reaction, yielding high enantioselectivity. The study explored the scope of 2-naphthols with substituents at the 3- and 7-positions, finding that 7-substituted 2-naphthols were particularly suitable substrates. The method provides a practical and efficient route for synthesizing optically active 7,7'- and 6,6'-substituted BINOLs, which are valuable in asymmetric synthesis. Mechanistic studies suggest that the reaction likely proceeds via an Fe(III)/Fe(IV) redox cycle, supported by the identification of a 2:1 complex of the ligand and Fe(OTf)2 as the active species. This work not only offers a novel synthetic approach for BINOLs but also provides insights into the oxidation properties of Fe(II) complexes.
10.3184/174751911X13182405888457
The research presents a study on the preparation of methyl (2-hydroxynaphthalen-1-yl)(aryl)methyl/benzylcarbamate derivatives using magnesium (II) 2,2,2-trifluoroacetate as an efficient catalyst. The methodology involves multi-component condensation reactions of aldehydes, 2-naphthol, and methyl/benzyl carbamate, resulting in the synthesis of various derivatives in high yields. The catalyst, Mg(OOCCF3)2, was prepared from trifluoroacetic acid and magnesium chloride and characterized through powder X-ray diffraction. The experiments involved optimizing reaction conditions such as catalyst amount, temperature, and solvent, with the best results achieved under solvent-free conditions at 100°C using 0.1 mmol of catalyst. Various aromatic aldehydes were tested, and the reaction was influenced by the electronic and steric properties of the aldehydes. The products were purified by simple filtration and crystallization from ethanol, and their structures were confirmed using NMR and IR spectroscopy, as well as elemental analysis. The study demonstrates an efficient method for synthesizing 1-carbamatoalkyl 2-naphthol derivatives with advantages such as good yields, simple procedure, shorter reaction times, and milder conditions.
10.1002/anie.201805203
The study presents a novel ring transposition process for synthesizing highly substituted 2-naphthols and BINOLs using lithium bases, specifically lithium diethylamide (LiNEt2) and lithium diisopropylamide (LDA). The process involves the conversion of readily available coumarins into 2-naphthols through a series of reactions where lithium bases act as both nucleophiles and bases. Initially, the lithium bases facilitate the ring opening of coumarins to form Z-cinnamamides, which serve as in situ directing groups. These Z-cinnamamides, with their conformational freedom, undergo a directed remote metalation and ring closure reaction, yielding aryl 2-naphthols in good to excellent yields. The study also provides mechanistic insights into the remote lateral metalation step, emphasizing the necessity of Z-cinnamamide for the reaction's success. Furthermore, the methodology is applied to the synthesis of highly substituted 3,3’-diaryl BINOL ligands, which are important in enantioselective synthesis and molecular recognition. The purpose of these chemicals is to demonstrate a new synthetic strategy that can efficiently produce complex molecular structures with potential applications in natural products, dyes, pigments, and as ligands and catalysts in asymmetric synthesis.
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