30625-92-4Relevant academic research and scientific papers
Oxovanadium complex-catalyzed aerobic oxidation of propargylic alcohols
Maeda, Yasunari,Kakiuchi, Nobuyuki,Matsumura, Satoshi,Nishimura, Takahiro,Kawamura, Takashi,Uemura, Sakae
, p. 6718 - 6724 (2002)
A catalytic system consisting of vanadium oxyacetylacetonate [VO(acac)2] and 3 A molecular sieves (MS3A) in acetonitrile works effectively for the aerobic oxidation of propargylic alcohols [R1CH-(OH)C≡CR2] to the corresponding carbonyl compounds under an atmospheric pressure of molecular oxygen. Although the reactivity of α-acetylenic alkanols (R1 = alkyl) is lower compared to that of the alcohols of R1 = aryl, alkenyl, and alkynyl, the use of VO(hfac)2 as a catalyst and the addition of hexafluoroacetylacetone improve the product yield in these cases. A catalytic cycle involving a vanadium(V) alcoholate species and β-hydrogen elimination from it has been proposed for this oxidation.
Gold-Catalyzed Ring Expansion of Enyne-Lactone: Generation and Transformation of 2-Oxoninonium
Luo, Kui,Cao, Tongxiang,Jiang, Huanfeng,Chen, Lianfen,Zhu, Shifa
supporting information, p. 5856 - 5859 (2017/11/10)
An efficient gold-catalyzed ring-expansion reaction of enyne-lactones to form 2-oxoninonium intermediates is reported. The 2-oxoninonium generated in this work could undergo further 6π electrocyclization and aromatization reaction to produce different aromatic compounds.
Metal-catalyzed formation of 1,3-cyclohexadienes: A catalyst-dependent reaction
Zhu, Shifa,Huang, Xiaobing,Zhao, Tian-Qi,Ma, Tongmei,Jiang, Huanfeng
supporting information, p. 1225 - 1233 (2015/03/04)
A metal-dependent and complementary catalytic method to synthesize the cyclohexadienes has been developed. When gold or indium salts were used as catalysts, 1,3-cyclohexadiene (1,3-CHD) could be obtained; when Cu(OTf)2 was used as the catalyst,
New synthetic approach for the construction of multisubstituted 2-acyl furans by the IBX-mediated cascade oxidation/cyclization of cis-2-En-4-yn-1-ols (IBX = 2-iodoxybenzoic acid)
Du, Xiangwei,Chen, Haoyi,Liu, Yuanhong
supporting information; experimental part, p. 9495 - 9498 (2009/10/06)
A new approach for the construction of multisubstituted 2-acyl furans through cis-2-En-4-yn-1-ols (IBX=2-iodoxybenzoic acid)-mediated oxidation/cyclization in dimethyl sulfoxidse (DMSO) was developed. The results show that the introduction of an alkyl group at Cl provided a satisfactory yield of furan of 60% at 90°C. It is seen that IBX act as an electrophile to promote the cycloaddition of carbonyl group to the alkyne moiety. The furan derivatives are found to be useful synthetic intermediates for access to the compounds bearing biological activity. The studies also elucidate this reaction mechanism and extend the scope of synthetic utility of multisubstituted 2-acyl furans.
Reactions of Carbenes with Oxetane and with Oxetane/ Methanol Mixtures
Kirmse, Wolfgang,Lelgemann, Rudolf,Friedrich, Klaus
, p. 1853 - 1863 (2007/10/02)
Ethoxycarbonylcarbene, bis(methoxycarbonyl)carbene, phenylcarbene (17a), diphenylcarbene (17b), fluorenylidene (17c), 2-furylcarbene (31a), 2-furyl(phenyl)carbene (31b), 4-oxo-2,5-cyclohexadienylidene (40), and 4,4-dimethyl-2,5-cyclohexadienylidene (53) were generated by photolysis of the appropriate diazo compounds.With neat oxetane, most of these carbenes react by competitive C-H insertion (B -> A, Scheme 1) and ylide formation (B -> C). 31a and 40 do not insert into C-H bonds; 31b does not attack oxetane but rearranges exclusively with formation of 26.The ylides undergo Stevens rearrangement to give tetrahydrofurans (C -> D) and α',β-elimination, leading to allyl ethers (C -> E).With oxetane/ methanol mixtures, the intervention of oxonium ions (H) is indicated by the formation of 1,3-dialkoxypropanes (I).The oxonium ions arise either by protonation of the ylides (C -> H) or by protonation of the carbenes (B -> G), followed by electrophilic attack of the carbocations (G) at oxetane (G -> H).The former route is followed by the alkoxycarbonylcarbenes and by 40; the ylides derived from the remaining carbenes do not react with methanol, owing to their rapid Stevens rearrangements.Protonation of the carbenes 17b, 31, and 53 is clearly indicated by their product ratios and, for 31, by the formation of isomeric ethers (33, 36).The more electrophilic carbenes discriminate but slightly between oxetane and methanol while the more nucleophilic carbenes (17b, 31, 53) prefer the protic methanol strongly over the aprotic oxetane. Key Words: Carbenes/ Oxygen ylides/ Stevens rearrangement/ Oxonium ions/ Insertion, O-H/ Ylides
