Non-metathesis reactions of ruthenium carbene catalysts and their application to the synthesis of nitrogen-containing heterocycles

Non-metathesis reactions of ruthenium carbene catalysts, such as olefin isomerization, hydrogenation, radical reaction, activation of silane, cyclopropanation, epimerization cocyclopropane, [3 + 2] cycloaddition, and cycloisomerization, are summarized. The utility of these reactions was demonstrated by the synthesis of indole using olefin isomerization and subsequent ring-closing metathesis, the synthesis of indoline using cycloisomerization, and the synthesis of the putative structure of fistulosin using cycloisomerization as a key step.     

Catalyzed synthesis of dihydrosilaazaanthracenes-silicon- and nitrogen-containing heterocycles

Conclusions 3-Methyl-4-dimethylphenyl-and 3-methyl-4-diphenylsilylpyridine have been dehydrocyclized over a chromium catalyst (composition 5% chromium (III) oxide, 5% Polirite, 1% potassium oxide, and 89%-Al₂O₃) to give 10,10-diniethyl-and 10-methyl-10-phenyl-9,10-dihydro-10-sila-2-azaanthracene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1905–1906, August, 1984.     

Multiple nitrogen-containing heterocycles: Metal and non-metal assisted synthesis

A wide variety of biological activities are possessed by N-, O-, and S-containing heterocycles and recently many reports appeared for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal and nonmetal became highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of multiple-nitrogen containing five-membered heterocylces in the presence of metal and nonmetal. It describes the formation of five-, six-, and seven-membered heterocyclic rings.     

Fluoroarenes in the synthesis of benzoannulated nitrogen-containing heterocycles

Methods for the synthesis of fluoro-containing benzazoles and benzazines from fluoroarenes (fluoroanilines, fluorobenzoic acids, fluoroacetophenones, fluorophenols, etc.) are described. The potentialities of the most important synthons are considered. Ways of constructing hetero- cycles with fluorine atoms in the annulated benzene fragment are discussed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 931–966, May, 2008.     

Palladium-catalyzed carboamination in the synthesis of nitrogen-containing heterocycles

An effective method for the stereoselective synthesis of various nitrogen-containing heterocycles by palladium-catalyzed carboamination is discussed. The method application examples to the synthesis of natural structures are presented.     

Preparation of nitrogen-containing heterocycles using ring-closing metathesis (RCM) and its application to natural product synthesis

Our synthetic study of nitrogen-containing heterocycles using ring-closing metathesis (RCM), such as chiral bicyclic lactams, azacycloundecenes, axially chiral macrolactams, 1,2-dihydroquinolines, 2-quinolinone and indoles, including a development of silyl-enol ether ene metathesis and isomerization of terminal olefins, are described. Their applications to natural product synthesis are also reported.     

The Ritter reaction in the synthesis of ortho-fused nitrogen-containing heterocycles

The acid-catalysed condensation of a 1,4- and a 1,5-ditertiary diol with various arylated nitriles is shown to provide a simple and novel route to reduced benz[f]indoles, naphth[1,8a,8-fg]indoles, benzo[4,5]cyclohepta[1,2-b]pyrroles, and benzo[g]quinolines.     

Catalytic synthesis of nitrogen-containing heterocycles (a review)

The process of the catalytic synthesis of a number of nitrogenous heterocyclic compounds based on the utilization of reactions involving the amination of oxygen-containing heterocycles, the dehydration cyclization of amino alcohols, the deamination of di- and polyamines, and the intermolecular dehydration cyclization of glycols with diamines have been considered.     

Synthesis of alkynyl ethers and low-temperature sigmatropic rearrangement of allyl and benzyl alkynyl ethers

Alpha-alkoxy ketones 3 can be transformed into 1-alkynyl ethers 5 by a two-step procedure involving formation of the enol triflate or phosphate and base-induced elimination. Performing the same reaction sequence with allylic alcohols (R2OH, R2 = allyl) furnishes instead gamma,delta-unsaturated carboxylic acid derivatives 6, derived from [3,3]-sigmatropic rearrangement of the intermediate allyl alkynyl ethers at -78 degrees C and trapping of the subsequently formed ketene with nucleophiles (Nu-H). Benzyl alkynyl ether 5 (R2 = benzyl) rearranges to indanone 7 upon heating to 60 degrees C.     

Saturated nitrogen-containing heterocycles. 16. Catalytic synthesis of N-arylperhydroacridines

Catalytic hydroamination of methylene-2,2-dicyclohexanone in the presence of substituted anilines or nitrobenzenes involves the formation of N-arylperhydroacridines. The stereoisomeric composition and yields of the latter are determined by the nature and position of the substituent in the aromatic ring of the aminating agent. The structure of isomeric N-arylperhydroacridines was established from data of ¹³C NMR spectroscopy and x-ray diffraction analysis.For Communication 15, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1094–1100, August, 1993.     

A palladium-catalyzed alkylation/direct arylation synthesis of nitrogen-containing heterocycles

A norbornene-mediated palladium-catalyzed sequence is described in which an alkyl-aryl bond and an aryl-heteroaryl bond are formed in one reaction vessel. The aryl-heteroaryl bond-forming step occurs via a direct arylation reaction. A number of six-, seven-, and eight-membered ring-annulated indoles, pyrroles, pyrazoles, and azaindoles were synthesized from the corresponding bromoalkyl azole and an aryl iodide.     

Development of new synthetic methods and its application to total synthesis of nitrogen-containing bioactive natural products

A group of naturally occurring substances containing nitrogen is widely distributed in plants as well as in fungi, animal, marine organisms, and insects, and many exhibit significant biological activity. These natural products with a huge variety of chemical structures include antibiotics, antitumor agents, immunostimulants, drugs affecting the cardiovascular and central nervous systems, analgesics etc. The diverse activities and low natural abundance of this group of natural products when coupled with their molecular complexity warrant development of new and efficient synthetic methods and strategy for the total synthesis of these products, in particular alkaloids. The purpose of this review is to describe some of our achievements in the total synthesis of the naturally-occurring bases including the Dendrobatid alkaloids pumiliotoxin B and allopumiliotoxin A, the anitibiotic streptazolin, the tricyclic marine alkaloids isolated from the ascidians such as fasicularin, lepadiformine, and cylindricine C, and the dimeric monoterpene alkaloid incarvillateine as well as the formal total synthesis of the spirocyclic marine alkaloids halichlorine and pinnaic acid, which are isolated from the Japanese marine sponge and the Okinawan bivalve, respectively.     

A new synthesis of nitrogen-containing heterocycles by means of organoaluminum reagents

Nitrogen-containing heterocycles can be derived in synthetically good yields from a variety of carbocyclic frameworks via the successive rearrangement-alkylation sequence of hydroxylamine carbonates with trialkylaluminums.     

Silver-catalyzed synthesis of disubstituted isoxazoles by cyclization of alkynyl oxime ethers

A facile and practical synthesis of 3,5-disubstituted isoxazoles via a silver-catalyzed cyclization and subsequent protonation of alkynyl oxime ethers has been developed. The methodology was successfully applied to the synthesis of a biologically active isoxazolecarboxylic acid.     

Gold-catalyzed intramolecular carbocyclization of alkynyl ketones leading to highly substituted cyclic enones

The reaction of the internal alkynyl ketones 1 (n=1) under the combined catalyst, AuCl3 and AgSbF6, gave the enones 2 in good to high yields, whereas that of the terminal alkynyl ketones 1 (n=0) under the combined catalyst, AuCl3 and AgOTf, afforded the cyclic enones 3.     

Quantum-chemical study of nitrosonium complexes derived from nitrogen-containing heterocycles

The affinities of a series of azines for nitrosonium ion (A _NO ⁺) were calculated by quantum-chemical methods, AM1 and ab initio. The A _NO ⁺ values were found to increase as the number of nitrogen atoms in the ring decreases and the donor power of substituents increases; ring fusion also increases A _NO ⁺. The best agreement between the calculated and experimental A _NO ⁺ values was attained with the use of AM1 calculations and ab initio methods with split polarization or diffuse functions. Substituted pyridines showed linear correlations between the calculated A _NO ⁺ values and substituent constants σ or σ⁺ or overall charges on the NO group in the complex. Linear correlations were also found between the calculated A _NO ⁺ values of azines and their experimental proton affinities.     

Aza-1,3-butadienes in synthesis of nitrogen-containing six-membered heterocycles (review)

We review and generalize literature data in recent years on application of heterodiene synthesis to obtain azines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1299–1307, October, 1992     

Saturated nitrogen-containing heterocycles. 11. The synthesis and structural studies of octahydroindolylalkanols

A catalytic synthesis was carried out for 3-(1-R-2-octahydroindolyl)alkanols using nickel promoted by ruthenium, Raney nickel, and Raney cobalt previously treated with acetic acid. An x-ray diffraction structural study of the acid tartrate of 3-(1-methyl-2-octahydroindolyl)-1-propanol gave the absolute configuration and conformational and structural features of the cation and tartrate anion.For Communication 10, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 66–70, January, 1985.