2699-13-0Relevant articles and documents
Nickel-Catalyzed Arylation of C(sp3)-O Bonds in Allylic Alkyl Ethers with Organoboron Compounds
Li, Xiaowei,Li, Yuxiu,Zhang, Zhong,Shi, Xiaolin,Liu, Ruihua,Wang, Zemin,Li, Xiangqian,Shi, Dayong
supporting information, p. 6612 - 6616 (2021/09/02)
A nickel-catalyzed cross-coupling of allylic alkyl ethers with organoboron compounds through the cleavage of the inert C(sp3)-O(alkyl) bonds is described. Several types of allylic alkyl ethers can be coupled with various boronic acids or their derivatives to give the corresponding products in good to excellent yields with wide functional group tolerance and excellent regioselectivity. The gram-scale reaction and late-stage modification of biologically active compounds further prove the practicality of this synthetic method.
Exploring the reaction pathways of Pd(II)-catalyzed cyclohexene oxidation with molecular oxygen: Vinylic and allylic oxidation, disproportionation and oxidative dehydrogenation
Da Silva,Berlini
, p. 7996 - 8005 (2016/09/12)
Palladium(ii) salts are able catalysts to promote different oxidative transformations of cyclohexene in the presence of molecular oxygen: vinylic and allylic oxidation and disproportionation. In this paper, we assessed the main aspects that govern these reactions, by using palladium salts (i.e. PdCl2, Pd(OAc)2, Pd(acac)2 and Pd(CF3COO)2) in protic solvents (i.e. CH3COOH and CH3OH). When carried out in CH3COOH solutions at 333 K, the Pd(ii)-catalyzed oxidation reactions preferentially convert cyclohexene to 2-cyclohexenil-1-acetate. Benzene was the secondary product. It was found that the efficiency of the palladium reoxidant followed the trend: Fe(NO3)3 > LiNO3 > CuCl2 > FeCl3. Pd(OAc)2 was the most active catalyst. Replacing Cu(OAc)2 by Fe(NO3)3 notably enhances the conversion of cyclohexene and the selectivity of 2-cyclohexenyl-1-acetate, reducing significantly the reaction time from 22 to 3 h. Conversely, when performed in CH3OH solutions, the reaction had its selectivity drastically changed; benzene and cyclohexane were the most selectively formed products (i.e. through disproportionation reaction). In this case, the reaction occurred at room temperature and in the absence of a reoxidant. Hence, Pd(CF3OO)2 is the most active and selective catalyst. The addition of the Fe(NO3)3 reoxidant and increasing the reaction temperature to 328 K resulted in the formation of 1,2-dimethoxycyclohexane and benzene as major products (i.e. allylic oxidation and oxidative dehydrogenation products, respectively). Catalytic cycles for these transformations were proposed based on experimental data and palladium chemistry.
InI3/me3sii-catalyzed direct alkylation of enol acetates using alkyl acetates or alkyl ethers
Onishi, Yoshiharu,Nishimoto, Yoshihiro,Yasuda, Makoto,Baba, Akio
supporting information; experimental part, p. 1223 - 1225 (2011/11/29)
A combined Lewis acid of InI3 and Me3SiI was used to catalyze the direct coupling reactions of enol acetates with alkyl acetates or alkyl ethers without generating metal waste. The easily-handled alkylating reagents enlarged the application area of this coupling reaction. 2011 The Chemical Society of Japan.
New oxidative transformations of alkenes and alkynes under the action of diacetoxyiodobenzene
Yusubov,Zholobova,Filimonova,Chi, Ki-Whan
, p. 1735 - 1742 (2007/10/03)
Treatment of alkenes and alkynes with diacetoxyiodobenzene activated by mineral and organic acids predominantly results in oxidative rearrangement. 1,4-Diphenylbutadiene in MeOH gives 3,4-dimethoxy-1,4-diphenylbut-1-ene.
Synthesis of allylic esters and ethers using polymer-supported selenium bromidet
Sheng, Shou-Ri,Huang, Xian
, p. 184 - 185 (2007/10/03)
The treatment of adducts from polymer-supported selenium bromide on olefins with anhydrous carboxylate or alcohol and oxidation of the resulting products afford allylic esters and ethers in good yield and purity.
Six- and five-membered 3-alkoxy-2-lithiocycloalkenes: New stable non-anionic β-functionalised organolithium compounds
Yus, Miguel,Ramón, Diego J,Gómez, Inmaculada
, p. 5163 - 5172 (2007/10/03)
Naphthalene-catalysed reductive lithiation of various functionalised chlorocycloalkenes 18 leads to the corresponding non-anionic β-alkoxyfunctionalised organolithium reagents 14. Their reaction with different electrophiles, such as water, aldehydes, keto
The reaction of cyclic allylic alcohols with aliphatic alcohols in the presence of cerium(III) chloride
Uzarewicz,Dresler
, p. 181 - 195 (2007/10/03)
Cyclic secondary and tertiary allylic alcohols react with primary aliphatic alcohols in the presence of cerium(III) chloride heptahydrate to give alkyl allylic ethers. When secondary or tertiary aliphatic alcohols are used 1,3-dienes are obtained from allylic alcohols heaving the 3-methyl-2-en-1-ol moiety (3-8, 13-15).
Stereodirecting Effect of a Substrate Methoxy Substituent on the Addition of Singlet Methylene to a Double Bond
Young, Terry A.,O'Rourke, Colleen,Gray, Nathan B.,Lewis, Brian D.,Dvorak, Curt A.,et al.
, p. 6224 - 6228 (2007/10/02)
The stereodirecting effects of substrate methoxy, hydroxy, methylthio, and methyl substituents were examined in the addition of 1:CH2 to the double bonds of substrates 1a-d.The carbene, generated by photolysis of CH2N2, inserted into the C-H bonds of solvent and substrate, added to the substrate double bond to give products 2a-d, and attacked the oxygen or sulfur atom of substrates 1a-c to produce ylide intermediates which underwent 2,3-sigmatropic rearrangement to give products 3a-c.A preference for addition syn to the methoxy group of substrate 1a was observed when the reaction was run in pentane solution (syn-2a/anti-2a, 1.14 +/- 0.02), while a preference for formation of anti-2a was observed in diethyl ether solution (syn-2a/anti-2a, 0.92 +/- 0.03).A preference for 1:CH2 addition anti to the substrate substituent was observed for substrates 1b-d in both pentane and ether solution.The effect of the methoxy substituent was also examined in the addition of 1:CH2 to syn-7-methoxynorbornene (5b).Explanations for the substituent effects are offered based on both steric hindrance and interaction between 1:CH2 and the substituent, including formation and subsequent reaction of the ylide intermediates.
Model Systems for Cytochrome P450 Dependant Mono-oxygenases. Part 7. Alkene Epoxidation by Iodosylbenzene Catalyzed by Ionic Iron(III) Tetrarylporphyrins Supported on Ion-exchange Resins
Leanord, Donald R.,Smith, John R. Lindsay
, p. 1917 - 1923 (2007/10/02)
Ionic iron(III) tetraarylporphyrins are readily adsorbed onto cross-linked polystyrene ion-exchange resins.These supported metalloporphyrins can act as heterogenous catalysts for the oxidation of organic compounds by iodosylbenzene in methanolic solution.Their catalytic activity for the epoxidation and allylic oxidation of cyclohexene and the epoxidation of (Z)-cyclooctene has been studied.With cyclohexene, epoxidation is favoured by increased cross-linking of the resin support, and allylic oxidation is shown to arise largely from an autoxidation which can be minimised by carrying out the reaction under nitrogen. (Z)-cyclooctene gives only epoxidation which is also favoured by increased cross-linking and is unaffected by changes in the surface area of the support.The influence of the support cross-linking on catalyst performance is discussed.Supproted anionic iron(III) porphyrins are poor catalysts unless they are sterically hindered with ortho-groups on the aromatic substituents.The fate of the oxidant in the heterogeneous oxidations is examined and comparison with the analogous homogeneous reactions suggests that some of the oxidant is consumed in oxidising the polymer support.A brief study of the oxidation of cyclohexene by iodosylbenzene catalyzed by a cation exchange resin in its acidic form, in the absence of metalloprophyrin, is reported.
