Iodine-catalyzed allylation of 1,3-dicarbonyl compounds with allylic alcohols at room temperature

A highly efficient iodine-catalyzed allylation of 1,3-dicarbonyl compounds with a wide variety of allylic alcohols has been developed. The reaction is operationally straightforward and proceeds under very mild conditions at room temperature in good to excellent yields (up to 99%) and regioselectivity.     

Heteropoly acid-catalyzed highly efficient alkylation of 1,3-dicarbonyl compounds with benzylic and propargylic alcohols

Various 1,3-dicarbonyl compounds reacted readily with benzylic and propargylic alcohols in the presence of 10 mol % of phosphomolybdic acid supported on silica gel (PMA/SiO₂) under mild reaction conditions to produce 2-benzylic- and 2-propargylic-1,3-dicarbonyl compounds in excellent yields and with high selectivity.     

Gold-catalysed allylic alkylation of aromatic and heteroaromatic compounds with allylic alcohols

Friedel-Crafts allylic alkylation of a wide variety of aromatic and heteroaromatic compounds with allylic alcohols catalysed by AuCl(3) (5 mol%) under mild conditions at room temperature was accomplished in good to excellent yields (up to 99%) and regioselectivity.     

Gold versus silver-catalyzed amination of allylic alcohols

Direct substitution of the hydroxy group in allylic alcohols by different nitrogenated nucleophiles is performed using low loadings of cationic gold(I) or silver salts as catalysts. Sulfonamides, carbamates and aromatic amines can be used as nucleophiles. Comparative studies between the best catalysts, cationic (triphenylphosphite)gold(I) complex and silver triflate, demonstrate that the former catalyst shows, in general, better performance than silver, working at lower loadings, in shorter reaction times and at lower temperatures. Representative allylic alcohols are used giving good γ-regioselectivity, specially in the case of penta-1,4-dien-3-ol and (E)-1-phenylbut-2-en-1-ol affording the corresponding allylic sulfonamides with total regio and stereoselectivity by a hydroamination mechanism. In the case of crotyl alcohol and (E)-4-phenylbut-3-en-2-ol mainly and exclusively α-substituted sulfonamides were obtained, respectively, by a cationic mechanism.     

Gold- and silver-catalyzed reactions of propargylic alcohols in the presence of protic additives

A wide range of primary, secondary and tertiary propargylic alcohols undergo a Meyer-Schuster rearrangement to give enones at room temperature in the presence of a gold(I) catalyst and small quantities of MeOH or 4-methoxyphenylboronic acid. The syntheses of the enone natural products isoegomaketone and daphenone were achieved using this reaction as the key step. The rearrangement of primary propargylic alcohols can readily be combined in a one-pot procedure with the addition of a nucleophile to the resulting terminal enone, to give β-aryl, β-alkoxy, β-amino or β-sulfido ketones. Propargylic alcohols bearing an adjacent electron-rich aryl group can also undergo silver-catalyzed substitution of the alcohol with oxygen, nitrogen and carbon nucleophiles. This latter reaction was initially observed with a batch of gold catalyst that was probably contaminated with small quantities of silver salt.     

Catalytic alkylation of benzylic C-H bonds with 1,3-dicarbonyl compounds utilizing oxygen as terminal oxidant

The oxidative alkylation of benzylic C-H bonds with 1,3-dicarbonyl compounds was developed using oxygen as the terminal oxidant in the presence of catalytic amounts of FeCl₂, CuCl and NHPI.     

Iodine-catalyzed allylic alkylation of sulfonamides and carbamates with allylic alcohols at room temperature

A highly efficient iodine-catalyzed allylic alkylation of a wide variety of sulfonamides and carbamates with allylic alcohols is reported herein. The reaction is operationally straightforward and proceeds under very mild conditions at room temperature in good to excellent yields (up to 99%).     

Low-valent titanium-mediated stereoselective alkylation of allylic alcohols

We have developed low-valent titanium-mediated 1,3-transpositive cross-coupling reactions of acyclic and cyclic allylic alcohols for the stereoselective introduction of ethyl, 2-silylethyl, 2-phenethyl, and alkenyl groups. Cross-coupling of an allylic alcohol with a vinylsilane or styrene derivative is particularly noteworthy, as an efficient cross-selective coupling of two alkenes has been elusive. The stereochemistry of the cross-coupling alkylation is consistent with syn addition/beta-elimination.     

An efficient Yb(OTf)3 catalyzed alkylation of 1,3-dicarbonyl compounds using alcohols as substrates

A highly efficient and environmentally friendly method for catalytic benzylation/allylation of 1,3-dicarbonyl compounds with alcohols has been developed by using Yb(OTf)₃ as a catalyst. The reactions proceed smoothly to give the desired products in moderate to excellent yields, mostly at room temperature. The catalyst can be recovered and reused at least six times without visible loss of catalytic activity for such reactions.     

Reactions of azidoazolopyridazines with 1,3-dicarbonyl compounds

Azidoazoloazines react with 1,3-dicarbonyl compounds to give cycloaddition products, 1,2,3-triazole derivatives, whose structures have been established by chemical transformations and spectroscopic data.     

Interaction of ethoxyacetaldehyde with 1,3-dicarbonyl compounds

It has been established that on interaction of ethoxyacetaldehyde with acetyl-acetone, acetoacetic ester, and benzoylacetone in the presence of piperidine acetate, ,-unsaturated compounds are formed, viz., 3-(2-ethoxy)vinyl substituted acetylacetone, acetoacetic ester, and benzoylacetone. Methods are proposed for the synthesis of 2,3,5-trisubstituted 4,5-dihydrofurans in the presence of trifluoroacetic or acetic acids by the cylization of the linear condensation products.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 308–311, March, 1986.     

Ruthenium-catalyzed addition of carboxylic acids or cyclic 1,3-dicarbonyl compounds to propargyl alcohols

Monomeric ruthenium(0) complexes containing redox-coupled dienone ligands were found to catalyze the regio-selective addition of carboxylic acids or cyclic 1,3-dicarbonyl compounds to propargyl alcohols.     

Ruthenium-catalyzed cycloaddition between propargylic alcohols and cyclic 1,3-dicarbonyl compounds via an allenylidene intermediate

Thiolate-bridged diruthenium complexes such as [Cp*RuCl(mu(2)-SR)(2)RuCp*Cl] (Cp* = eta(5)-C(5)Me(5); R = Me, (n)Pr, (i)Pr) and [Cp*RuCl(mu(2)-S(i)Pr)(2)RuCp*(OH(2))]OTf (OTf = OSO(2)CF(3)) promote the cycloaddition between propargylic alcohols and cyclic 1,3-dicarbonyl compounds to give either the corresponding 4,6,7,8-tetrahydrochromen-5-ones or 4H-cyclopenta[b]pyran-5-ones in high yields with complete regioselectivity. This catalytic cycloaddition provides a simple and one-pot synthetic protocol for a variety of substituted chromenones and cyclopenta[b]pyranones.     

Reaction of trifluoromethyl-containing 1,3-dicarbonyl compounds with bis-hydrazides

Carbonic dihydrazide reacted with 2 equiv of trifluoroacetylacetone to give a compound containing 5-hydroxy-4,5-dihydropyrazole and keto enehydrazine fragments. Analogous 2 : 1 condensations of trifluoro-acetylacetone and 4-ethoxy-1,1,1-trifluorobut-3-en-2-one with oxalohydrazide and malonohydrazide afforded bis(5-hydroxy-4,5-dihydropyrazole) structures as two diastereoisomers.     

Reaction of fluoroalkyl-containing 1,3-dicarbonyl compounds with benzylideneacetone

The reaction of fluoroalkyl-containing 1,3-dicarbonyl compounds with benzylideneacetone with the use of pyridine or triethylamine as a catalyst gave new 3-fluoroalkyl-4-ethoxycarbonyl(acyl)-5-phenylcyclohexan-3-ol-I-ones in yields of 16–33%. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 992–994, May, 1997.     

Interaction of fluorine-containing 1,3-dicarbonyl compounds with polyamines

In the reaction of fluorinated copper(II) 1,3-diketonates with diethylenetriamine (or triethylenetetramine) in CHCl₃, N,N-bis(1,3-aminovinylketones) are formed in 21–35% yields. Fluorine-containing 1,3-diketones and 1,3-ketoesters, upon interaction with polyamines without solvent, undergo acid cleavage, forming the corresponding amides. The copper(II) 1,3-ketoesterates are readily cleaved in CHCl₃ at 25°C in excess triethylenetetramine or ethylenediamine.Department of Fine Organic Synthesis, Institute of Organic Chemistry, Ural Branch, Russian Academy of Sciences, 620219 Ekaterinburg. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2591–2596, November, 1992.     

Condensation of propargylic alcohols with 1,3-dicarbonyl compounds and 4-hydroxycoumarins in ionic liquids (ILs)

Propargylic alcohols are activated toward 1,3-diketones by Lewis or Brønsted acidic ionic liquids (ILs) without an added catalyst, but significantly better conversions are achieved with metallic triflates [in particular Sc(OTf)₃ and Ln(OTf)₃] and bismuth nitrate in imidazolium ILs. The scope of this condensation reaction was investigated with a variety of propargylic alcohols and a host of acyclic and cyclic dicarbonyl compounds. Concomitant cycloisomerization leading to tetrasubstituted furans was observed with the propargylic alcohols 1b and 1c in reaction with 1,3-diketone 2b and the β-ketoester 2c. With propargylic alcohol 1c, propargylation, cycloisomerization, or dienone formation were observed, depending on the structure of the 1,3-dicarbonyl compound. The [BMIM][PF₆]/Bi(NO₃)₃·5H₂O system proved efficient for propargylation, vinylation, and alkylation of 4-hydroxycoumarins. The recycling and reuse of the IL are added advantages of this method.     

Polymer-incarcerated gold-palladium nanoclusters with boron on carbon: a mild and efficient catalyst for the sequential aerobic oxidation-Michael addition of 1,3-dicarbonyl compounds to allylic alcohols

We have developed a polymer-incarcerated bimetallic Au-Pd nanocluster and boron as a catalyst for the sequential oxidation-addition reaction of 1,3-dicarbonyl compounds with allylic alcohols. The desired tandem reaction products were obtained in good to excellent yields under mild conditions with broad substrate scope. In the course of our studies, we discovered that the excess reducing agent, sodium borohydride, reacts with the polymer backbone to generate an immobilized tetravalent boron catalyst for the Michael reaction. In addition, we found bimetallic Au-Pd nanoclusters to be particularly effective for the aerobic oxidation of allylic alcohols under base- and water-free conditions. The ability to conduct the reaction under relatively neutral and anhydrous conditions proved to be key in maintaining good catalyst activity during recovery and reuse of the catalyst. Structural characterization (STEM, EDS, SEM, and N(2) absorption/desorption isotherm) of the newly prepared PI/CB-Au/Pd/B was performed and compared to PI/CB-Au/Pd. We found that while boron was important for the Michael addition reaction, it was found to alter the structural profile of the polymer-carbon black composite material to negatively affect the allylic oxidation reaction.     

Reaction of 1,3-dicarbonyl compounds with nitryl chloride

Reaction of 1,3-dicarbonyl compounds with nitryl chloride through substitution on the activated methylene group, resulted in the formation of chloro, dichloro and oximino derivatives.

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Die Reaktion der 1,3-Dicarbonylverbindungen mit Nitrylchlorid

Zusammenfassung Umsetzung von 1,3-Dicarbonylverbindungen mit Nitrylchlorid ergab die entsprechende Chloro-, Dichloro- und Oximinoderivate in einer Substitutionsreaktion an der aktivierten Methylengruppe.