Diazodicarbonyl Compounds Research Articles

Diazo Strategy for Intramolecular Azirine Ring Expansion: Rh(II)-Catalyzed Synthesis of 2-Hydroxy-3-oxo-2,3-dihydro-1H-pyrrole-2-carboxylates.

A diazo strategy for the intramolecular azirine ring expansion was developed. Azirinyl-substituted diazodicarbonyl compounds, prepared from diazoacetylazirines, were converted in excellent yields to 2-hydroxy-3-oxo-2,3-dihydro-1H-pyrrole-2-carboxylates under Rh catalysis in the presence of water. According to DFT calculations, the formation of only pyrrolinone derivatives and the absence of O-H insertion products of Rh carbene into water are due to the low Gibbs free energy of the transition state for the concerted opening of the azirine ring and recyclization to pyrrolone in intermediate Rh complexes.

Iridium(III)-Catalyzed C−H Functionalization of Triarylphosphine Oxides with Diazo Dicarbonyl Compounds: Synthesis of α-Aryl 1,3-Dicarbonyl Derivatives

AbstractA novel (pentamethylcyclopenta-1,3-dienyl)iridium(III)-catalyzed direct C–H functionalization of triarylphosphine oxides with diazo dicarbonyl compounds through carbene insertion has been developed. This strategy provides a simple and efficient route to the construction of α-arylated 1,3-dicarbonyl compounds, which are important building blocks in pharmaceutical chemistry.

In(III)‐Catalyzed O‐Annulation of Cyclic Diazodicarbonyls with 2‐Naphthol, 6‐Quinolinol, β‐Tetralone, and 9‐Phenanthrol to Access Diverse Benzochromones

In(III)‐Catalyzed O‐annulation of cyclic diazodicarbonyl compounds with 2‐naphthols, 6‐quinolinol, β‐tetralone, and 9‐phenanthrol is developed. This novel synthetic strategy paves a facile and desired access to diverse and functionalized benzochromones. This imperative protocol involves domino carbene generation, ketene formation through Wolff‐rearrangement, nucleophilic addition, H‐migration, intramolecular cyclization, and elimination of water.

Tandem Carbenoid C-H Functionalization/Conia-ene Cyclization of N-Propargyl Indoles Generates Pyrroloindoles under Cooperative Rh(II)/Zn(II) Catalysis.

The decomposition of diazodicarbonyl compounds in the presence of various metal catalysts has become a reliable method for the functionalization of indoles via carbenoid intermediates. Exploiting the nucleophilic reactivity of the in situ generated malonic ester product formed, we herein report a tandem C-H functionalization/Conia-ene cyclization of N-alkyne tethered indoles. This double functionalization of diazodicarbonyls generates a range of pyrrolo[1,2-a]-, pyrido[1,2-a]-, and azepino[1,2-a]indole products with good synthetic efficiency.

Ruthenium catalyzes the synthesis of γ-butenolides fused with cyclohexanones.

Ruthenium(II)-catalyzed reactions of cyclic diazodicarbonyl compounds with β-ketoamides for chemo- and stereoselective construction of cyclohexanone-fused γ-butenolides are described. This study represents the first example of the addition of an enol substrate which is formed by the tautomerization of the β-ketoamides to the electrophilic carbene center for unusual cyclization through amide cleavage. The combined experimental and computational studies shed light on the mechanistic pathway favouring the unusual ring formation reaction instead of the involvement of the general carbonyl ylide intermediates for the product generation.

Ruthenium Complexes Immobilized on Functionalized Knitted Hypercrosslinked Polymers as Efficient and Recyclable Catalysts for Organic Transformations

AbstractA hypercrosslinked polymer (HCP)‐immobilized ruthenium catalyst (HCP–PPh3–Ru) was prepared from benzene and triphenylphosphine (PPh3) through a one‐step external cross‐linking reaction. The structure and composition of the catalyst were fully characterized by many physicochemical methods. HCP–PPh3–Ru was found to possess high Brunauer–Emmett–Teller (BET) surface area, large pore volume, and low skeletal density. Moreover, the Ru catalyst was also featured some advantages, such as low synthetic cost and good chemical and thermal stability. HCP–PPh3–Ru was then used as a recoverable and effective catalyst for the synthesis of 2,4‐diaryl‐substituted pyridines from acetophenones, ammonium acetate (NH4OAc) and dimethylformamide (DMF), and the cycloaddition reaction of diazodicarbonyl compounds with olefins to afford dihydrofurans. In addition, a combination of HCP–PPh3–Ru and Amberlyst‐15 enabled us to establish a simple protocol for the direct synthesis of carbazole derivatives from diazodicarbonyl compound, alkyl vinyl ether and indole. In these selected reactions, the catalyst was easily recovered and reused several times without significant activity loss.magnified image

ChemInform Abstract: Dichlorination of α‐Diazo‐β‐dicarbonyls Using (Dichloroiodo)benzene.

AbstractA mild and efficient Lewis‐base or Lewis‐acid‐catalyzed chlorination of diazodicarbonyl compounds is described.

ChemInform Abstract: Regioselective Synthesis of Highly Functionalized Furans Through the RuII‐Catalyzed [3 + 2] Cycloaddition of Diazodicarbonyl Compounds.

AbstractA novel cascade process for the regioselective synthesis of highly functionalized furans from readily available acyclic and cyclic diazodicarbonyl compounds and terminal alkynes is described.

Domino reactions of diazodicarbonyl compounds with α,β-unsaturated δ-amino esters: a convenient way towards 2-oxopiperidines, dihydropyridinones and isoquinolinediones.

Thermal decomposition of a series of diazodicarbonyl compounds in the presence of α,β-unsaturated δ-amino esters and sodium hydride gives rise to a variety of nitrogenous heterocycles. The direction of these processes is highly dependent on the structure of the initial reagents giving rise to the formation of multi-functionalized 2-oxopiperidines, 5,6-dihydropyridin-2(1H)-ones or tetrahydroisoquinoline-1,6(2H,8aH)-diones. The reactions occur in domino processes involving the Wolff rearrangement of diazocarbonyl compounds, NaH-catalyzed anti-stereoselective intramolecular Michael addition to the α,β-unsaturated system of amino esters, and in some cases also cycloelimination and intramolecular Claisen condensation of the initial products formed.

Copper-catalyzed condensation of imines and α-diazo-β-dicarbonyl compounds: modular and regiocontrolled synthesis of multisubstituted pyrroles.

In the presence of a copper(ii) catalyst, enolizable imines bearing various N-substituents and α-diazo-β-ketoesters undergo denitrogenative and dehydrative condensation to afford highly substituted pyrroles in moderate to good yields with exclusive regioselectivity. The reaction likely involves nucleophilic addition of the imine nitrogen to a copper carbenoid, tautomerization of the resulting azomethine ylide to an α-enaminoketone, and a subsequent enamine-ketone cyclocondensation. With Yb(OTf)3 as a unique cocatalyst, α-diazo-β-diketones also participate in the same condensation reaction. The present reaction is applicable to acyclic, exocyclic, and endocyclic imines with tolerance of a broad range of functional groups and heterocyclic moieties, thus opening a new convenient route for the synthesis of the lamellarin family of natural products.

ChemInform Abstract: Novel One‐Pot Synthesis of Diverse γ,δ‐Unsaturated β‐Ketoesters by Thermal Cascade Reactions of Diazodicarbonyl Compounds and Enol Ethers: Transformation into Substituted 3,5‐Diketoesters.

AbstractWolff rearrangement of α‐diazo‐β‐ketoesters (I) and (IV) followed by trapping of the ketene intermediates with enol ethers (II) and (V) generates a variety of trans‐γ,δ‐unsaturated β‐ketoesters (III) and (VI), respectively.

Ruthenium(II)‐Catalyzed Protocol for Preparation of Diverse α,β‐ and β,β‐Dihaloenones from Diazodicarbonyls

AbstractEfficient one‐step syntheses of α,β‐ and β,β‐dihaloenones were achieved by ruthenium(II)‐catalyzed reactions between cyclic or acyclic diazodicarbonyl compounds and oxalyl chloride or oxalyl bromide in moderate to good yields. This methodology offers several significant advantages, which include ease of handling, mild reaction conditions, one‐step reaction, and the use of an effective and non‐toxic catalyst. The synthesized compounds were further transformed into highly functionalized novel molecules bearing aromatic rings on the enone moiety using the Suzuki reaction.magnified image

One‐Pot Synthesis of Multi‐Substituted 4‐Pyrones by a Gold‐ Catalyzed Cascade of Wolff Rearrangement/[4+2] Cycloaddition/ Elimination Reactions

AbstractAn efficient one‐pot method is described for the synthesis of a variety of di‐ and trisubstituted 4‐pyrones based on the gold‐catalyzed cascade reactions between cyclic or acyclic diazodicarbonyl compounds and vinyl ethers. The key strategy used involves the gold‐catalyzed Wolff rearrangement of diazo compounds followed by [4+2] cycloaddition and elimination. This methodology is also applied to the synthesis of tetrasubstituted 4‐pyrones.magnified image

Regioselective Synthesis of Highly Functionalized Furans Through the RuII‐Catalyzed [3+2] Cycloaddition of Diazodicarbonyl Compounds

AbstractA novel method for the RuII‐catalyzed regioselective synthesis of highly functionalized furans from readily available cyclic and acyclic diazodicarbonyl compounds and terminal alkynes is described. The devised protocol offers a straightforward means to the construction of a variety of diverse furan derivatives through powerful cascade processes, including the formation of ruthenium carbenoid, cyclopropenation, ring‐opening metathesis, and cyclization.

ChemInform Abstract: Efficient One‐Pot Synthesis of Multi‐Substituted Dihydrofurans by Ruthenium(II)‐Catalyzed [3 + 2] Cycloaddition of Cyclic or Acyclic Diazodicarbonyl Compounds with Olefins.

AbstractThe reaction can be carried out under conventional or microwave‐assisted conditions.

Formal [4 + 1]-Cycloaddition of Homopropargyl Alcohols to Diazo Dicarbonyl Compounds Giving Substituted Tetrahydrofurans

A novel formal [4 + 1]-cycloaddition of readily available homopropargyl alcohols with diazo dicarbonyl compounds is described, which involves tandem O-H insertion/Conia-ene cyclization under cooperative Rh(II)/Zn(II) catalysis. This reaction provides easy access to various substituted tetrahydrofurans and exhibits complete E-selectivity in the case of nonterminal alkynes.

Novel one-pot synthesis of diverse γ,δ-unsaturated β-ketoesters by thermal cascade reactions of diazodicarbonyl compounds and enol ethers: transformation into substituted 3,5-diketoesters.

Sequential Wolff rearrangement of α-diazo-β-ketoesters followed by trapping of the ketene intermediates with enol ethers generated a variety of γ,δ-unsaturated β-ketoesters. This method involves a novel thermal cascade reaction and allows the synthesis of γ,δ-unsaturated β-ketoesters with trans-stereochemistry under catalyst-free conditions. The synthesized compounds were further transformed into novel 3,5-diketoesters, which were used for the synthesis of naturally occurring 2-pyrone and 1-naphthoic acid ester.

Less reactive dipoles of diazodicarbonyl compounds in reaction with cycloaliphatic thioketones - First evidence for the 1,3-oxathiole-thiocarbonyl ylide interconversion.

Acyclic diazodicarbonyl compounds react at room temperature with cycloaliphatic thioketones, e.g. 2,2,4,4-tetramethyl-3-thioxocyclobutanе-1-one and adamantanethione, via a cascade process in which the key step is a 1,5-electrocyclization of the intermediate thiocarbonyl ylide leading to tetrasubstituted spirocyclic 1,3-oxathioles. The most reactive diazodicarbonyl compound was diazoacetylacetone. In the case of dimethyl diazomalonate competitive 1,3-electrocyclization yielded the corresponding thiirane at elevated temperature, which after spontaneous desulfurization produced a tetrasubstituted alkene. To explain the observed temperature dependence of the main reaction product type obtained from dimethyl diazomalonate and 2,2,4,4-tetramethyl-3-thioxocyclobutanе-1-one as well as to verify reversibility of the thiocarbonyl ylide and 1,3-oxathiole interconversion, the calculations of the energy profile for the transformation of 1,3-oxathiole to alkene were performed at the DFT PBE1PBE/6-31G(d) level.

Efficient One‐Pot Synthesis of Multi‐Substituted Dihydrofurans by Ruthenium(II)‐Catalyzed [3+2] Cycloaddition of Cyclic or Acyclic Diazodicarbonyl Compounds with Olefins

AbstractRuthenium(II)‐phosphine complexes‐catalyzed [3+2] cycloadditions were conducted to synthesize a variety of dihydrofurans by reactions of cyclic or acyclic diazodicarbonyl compounds with olefins. This method represents a direct and efficient one‐pot synthesis for multi‐substituted dihydrofurans under mild reaction conditions with an excellent regioselectivity. Furthermore, to reduce reaction times and increase yields of dihydrofurans, microwave‐assisted tris(triphenylphosphine)ruthenium(II) chloride/ 1‐butyl‐3‐methylimidazolium tetrafluoroborate {Ru(PPh3)3Cl2/[Bmim]BF4}‐catalyzed reactions were also developed. The synthesized dihydrofurans can be readily converted into biologically interesting tetrahydroindoles.magnified image

Efficient and Facile Synthesis of α-Chloroenones Bearing β-Carbonates or β-Carbamates

E-mail: yrlee@yu.ac.krReceived September 5, 2012, Accepted October 4, 2012Efficient synthesis of α-chloroenones bearing β-carbonates or β-carbamates was achieved by rhodium(II)-catalyzed reaction of cyclic diazodicarbonyl compounds with a variety of chloroformates or carbamyl chloridesin good yields. These reactions provided a useful and rapid route to β-substituted α-haloenones. Key Words : Rhodium(II)-catalyzed reaction, Diazodicarbonyl compounds, α-chloroenonesIntroductionα-Halo enones have been widely used as valuable andversatile intermediates in the synthesis of α-carbon sub-stituted enones