Synthesis Of Naphthalenes Research Articles

ChemInform Abstract: The Baylis—Hillman Acetates in Organic Synthesis: Unprecedented Sodium Nitrite Induced Intramolecular Friedel—Crafts Cyclization of Secondary Nitro Compounds.

AbstractThe presented facile protocol delivers naphthalenes, phenanthrenes, and carbazoles.

ChemInform Abstract: Synthesis of Naphthalene and Indene Precursors to Naphthoic and Indenoic Acids.

Abstract As part of ongoing research to investigate structural requirements for lactate dehydrogenase inhibition by highly substituted naphthoic and indenoic acids, certain naphthalene and indene precursors to those types of compounds are required. Described here are efficient preparations of 1-naphthoic acid precursors 6-benzyl-2,3-dimethoxy-1-propylnaphthalenes, including compounds with substituted benzyl groups and 7-benzyl-2,3-dimethoxy-1-propylnaphthalene. Also described are the syntheses of indenoic acid precursors 2-benzyl-5,6-dimethoxy-7-propyl-1 H -indenes, including compounds with substituted benzyl groups. These compounds were made from the key intermediates 6,7-dimethoxy-5-propyl-1-tetralone, 6,7-dimethoxy-8-propyl-1-tetralone, and 5,6-dimethoxy-4-propyl-1-indanone.

ChemInform Abstract: Cobalt‐Catalyzed Annulation of Aryl Iodides with Alkynes.

AbstractA cobalt‐catalyzed approach for the concise synthesis of naphthalenes by the annulation of aryl iodides with symmetrical alkynes is disclosed.

The Role of Acetylides in Dual Gold Catalysis: A Mechanistic Investigation of the Selectivity Difference in the Naphthalene Synthesis from Diynes

AbstractUnder the conditions of dual activation catalysis with oxygen nucleophiles, β‐substituted naphthalenes were obtained from 1,2‐diethinyl arenes. Mechanistic studies, which include isotope labeling experiments, support that dual activation leads to β‐substituted naphthalenes, whereas α‐naphthalenes are formed by π activation only, and no gold acetylide or dual activation is involved in the formation of the α‐substituted products. Additional experiments on substrates that led to dibenzopentalenes support these mechanistic insights.

First synthesis of naphthalene annulated oxepins

Highly condensed oxepins have been prepared in good yields from their corresponding diols by etherification using p-toluenesulfonic acid.

Naphthalene and 2,3-dihydrobenzo[b][1,4]dioxine derivatives with extended side chains as new scaffolds of CB2-selective ligands

Herein, we report the synthesis of naphthalene, dihydrobenzodioxine and fluorene derivatives with extended side chains and their biological evaluation as ligands of CB1 and CB2 receptors.

Synthesis of naphthalene and indene precursors to naphthoic and indenoic acids

As part of ongoing research to investigate structural requirements for lactate dehydrogenase inhibition by highly substituted naphthoic and indenoic acids, certain naphthalene and indene precursors to those types of compounds are required. Described here are efficient preparations of 1-naphthoic acid precursors 6-benzyl-2,3-dimethoxy-1-propylnaphthalenes, including compounds with substituted benzyl groups and 7-benzyl-2,3-dimethoxy-1-propylnaphthalene. Also described are the syntheses of indenoic acid precursors 2-benzyl-5,6-dimethoxy-7-propyl-1H-indenes, including compounds with substituted benzyl groups. These compounds were made from the key intermediates 6,7-dimethoxy-5-propyl-1-tetralone, 6,7-dimethoxy-8-propyl-1-tetralone, and 5,6-dimethoxy-4-propyl-1-indanone.

Cobalt-catalyzed annulation of aryl iodides with alkynes

A cobalt-catalyzed approach for the concise synthesis of naphthalenes by the annulation of aryl iodides with alkynes is disclosed. In the reaction, manganese reductant and MeCN solvent are necessary to proceed efficiently, which tolerates various functional groups, for example, boronate ester. Mechanistic investigation indicates that the transformation employs electrophilic aromatic substitution (SEAr) in the aromatic C–H bond replacement step.

ChemInform Abstract: Palladium‐Catalyzed Selective Synthesis of Naphthalenes and Indenones and Their Luminescent Properties.

AbstractUnder a nitrogen atmosphere, the palladium‐catalyzed reaction of o‐haloacetophenones (I) with terminal alkynes in the presence of wet secondary cyclic amines gives β‐arylnaphthalenes.

Palladium‐Catalyzed Selective Synthesis of Naphthalenes and Indenones and Their Luminescent Properties

AbstractSelective synthesis of functionalized naphthalenes and indenones by palladium‐catalyzed cyclization of o‐haloacetophenones and terminal alkynes in the presence of a secondary amine is reported. Under a nitrogen atmosphere, the palladium‐catalyzed reaction of o‐haloacetophenones with terminal alkynes in the presence of wet secondary aminesgenerated 1‐(dialkylamino)‐3‐aryl/alkylnaphthalenes. When the reaction was conducted in air, 1‐indenone‐3‐carbaldehydes were obtained. The synthesized β‐arylnaphthalenes 4a–f emit light in a range from 386 to 452 nm with quantum yields from 0.10 to 0.48 in cyclohexane. The absorption and emission efficiency of 4d were finely tuned by the acidity of the environment, and this might be useful in the use of 4d as a fluorescent pH sensor.

ChemInform Abstract: Regioselective Synthesis of Naphthalenes from Modified Baylis—Hillman Adducts via a Pd‐Catalyzed Cyclization: 5‐exo‐Carbopalladation, C(sp3)—H Activation to Cyclopropane, Ring‐Opening, and Aromatization Cascade.

AbstractThe process affords polysubstituted naphthalene derivatives as main products in low to moderate yields.

Regioselective synthesis of naphthalenes from modified Baylis–Hillman adducts via a Pd-catalyzed cyclization: 5- exo-carbopalladation, C(sp 3)–H activation to cyclopropane, ring-opening, and aromatization cascade

Modified Baylis–Hillman adducts having 2-bromophenyl acetonitrile moiety at the primary position underwent a Pd-catalyzed cascade reaction to provide poly-substituted naphthalene derivatives in reasonable yields. The reaction involved a sequential 5- exo-carbopalladation, C(sp 3)–H activation to cyclopropane, ring-opening and concomitant aromatization processes.

ChemInform Abstract: Total Synthesis of Michellamines A-C, Korupensamines A-D, and Ancistrobrevine B.

Efficient syntheses of the title compounds have been developed. Several strategies for preparation of each of the naphthalene and tetrahydroisoquinoline (THIQ) portions were developed. Initial attempts to use benzyne plus furan cycloaddition reactions were thwarted by the unfavorable sense of the regiochemical outcome. An interesting annulation reaction of benzynes derived from 2,4-dibromophenol derivatives formed the core of the shortest naphthalene synthesis. An alternative annulation initiated by the addition of a benzylic sulfone anion to methyl crotonate led to an efficient naphthol synthesis amenable to large scale. The THIQ synthesis of Bringmann was used initially and subsequently complemented by a route whose key step involved the opening of N-tosyl-2-methylethyleneimine by a 3,5-dimethoxyphenylcuprate reagent. The results from a variety of aryl cross-coupling reactions are described. Suzuki coupling of the boronic acid derived from the naphthalene moiety with a THIQ-iodide was the most generally...

One-Pot Synthesis of Naphthalenes from Baylis-Hillman Adducts via Pd-Mediated Successive Allylation and Arylation

Introduction of nucleophiles at the primary position of Baylis-Hillman adducts has been carried out by the nucleophilic substitution reaction from the acetate or primary bromide derivative of Baylis-Hillman adduct. Palladiumassisted introduction of nucleophiles has also been reported in the Baylis-Hillman chemistry via the corresponding πallylpalladium intermediate. Thus we reasoned that one-pot synthesis of dihydronaphthalene could be carried out by Pd-mediated successive allylation and arylation protocol from the reaction of 1a, the acetate of Baylis-Hillman adduct of 2-bromobenzaldehyde, and dimethyl malonate (2a) as in Scheme 1. The reaction between 1a and 2a produced naphthalene derivative 5a (73%) in a one-pot, under the influence of Pd(OAc)2/TBAB/ K2CO3 in DMF at 90 C (3 h), instead of the expected dihydronaphthalene 4a. The reaction mechanism for the one-pot formation of 5a can be postulated as the following successive processes: (i) allylation of 2a via the π-allylpalladium intermediate (I) to produce the substitution product 3a, (ii) Pd-mediated arylation of 3a to dihydronaphthalene 4a via the intermediate (II), and (iii) dealkoxycarbonylation and concomitant aerobic oxidation process to give the final product 5a. In order to clarify the last step of the concomitant dealkoxycarbonylation and aerobic oxidation, we examined the reaction in more detail as in Scheme 2. The reaction of compound 3a, prepared by nucleophilic substitution reaction from 1a and 2a (K2CO3, CH3CN, rt, 3 h, 78%), 1,7,9

Synthesis of Naphthalenes through Three-Component Coupling of Alkynes, Fischer Carbene Complexes, and Benzaldehyde Hydrazones via Isoindole Intermediates

The synthesis of naphthalene derivatives through three-component coupling of 2-alkynylbenzaldehyde hydrazones with carbene complexes and electron-deficient alkynes has been examined. The reaction involves formation of an isoindole derivative, followed by intramolecular Diels-Alder reaction, followed by nitrene extrusion. The reaction was highly regioselective using unsymmetrical alkynes.

A Facile Access to Medium- and Large-Size Naphthalenacarbocycles via Lewis Acid Mediated Ring-Expansion Reaction of Bicyclic Vinylidenecyclopropanes

Ring-expansion reactions of bicyclic vinylidenecyclopropanes in the presence of Lewis acid was investigated, providing an efficient method for the synthesis of naphthalenes with annulated carbocycles of various ring sizes in good to excellent yields under mild conditions.

New Insights into the Reaction Mechanisms of Phenylium Ions with Benzene

The chemistry of phenylium (benzen-1-ylium) cations with benzene is investigated by using a guided ion beam tandem mass spectrometer. The main ionic products from the reaction of C6H5+ with C6H6 are observed at m/z 155 (covalent adduct C12H11+), 154 (C12H10+), 153 (C12H9+), 129 (C10H9+), and 115 (C9H7+). We propose a mechanism according to which channels at m/z 154-115 are formed by elimination of stable neutral molecules (such as H2, C2H2, C3H4) from the collision complex C12H11+, for which the most plausible structure is protonated biphenyl. The proposed mechanism is demonstrated by using partial isotopical labeling of reagents to look for possible H/D atom scrambling. Almost the same ions are produced when benzene is chemically ionized at atmospheric pressure in an APCI source from which oxygen is excluded. Because an ion trap analyzer is coupled to this source, tandem MS experiments can be performed, allowing structural details to be established. Moreover, the use of partially deuterated reagents has allowed the detection of minor reactive channels resulting from charge exchange and H-/D- hydride-transfer processes. Theoretical calculations show that the most stable structure for ions at m/z 129 C10H9+ is that of protonated naphthalene, resulting from the loss of an acetylene molecule by the condensation product, with a reaction exothermicity of 1.27 eV. We have found a possible barrierless pathway for such a channel that might be viable for the synthesis of naphthalene, the smallest PAH, even at low collision energies and therefore would be of particular astrochemical relevance.

Synthesis of Naphthalenes and 2‐Naphthols by the Electrophilic Cyclization of Alkynes.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Synthesis of naphthalenes and 2-naphthols by the electrophilic cyclization of alkynes.

[reactions: see text] A wide variety of substituted naphthalenes are readily prepared regioselectively under mild reaction conditions by the 6-endo-dig electrophilic cyclization of appropriate arene-containing propargylic alcohols by ICl, I2, Br2, NBS, and PhSeBr. 3-Iodo-2-naphthols have also been prepared in excellent yields by the cyclization of analogous 1-aryl-3-alkyn-2-ones. This methodology readily accommodates various functional groups and has been successfully extended to the synthesis of substituted carbazoles and dibenzothiophenes.

Towards a Synthesis of Naphthalene Derived Natural Products

Dieckmann-type cyclization reactions have been employed in the synthesis of the alkyl substituted naphthoquinone 11 and the naphthalenes 10 and 12. Various conditions for the benzylic oxidation of these compounds have been investigated with a view towards the synthesis of some naphthalene based natural products.