- Gold(I)-catalyzed intermolecular cycloaddition of allenamides with α,β-unsaturated hydrazones: Efficient access to highly substituted cyclobutanes
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α,β-Unsaturated N,N-dialkyl hydrazones undergo a mild [2 + 2] cycloaddition to allenamides when treated with a suitable gold catalyst. The method, which represents the first application of N,N-dialkyl hydrazones in gold catalysis, is compatible with a wide variety of substituents at the alkenyl moiety of the hydrazone component, proceeds with excellent levels of regio- and diastereoselectivity, and provides densely substituted cyclobutanes with good to excellent yields.
- Bernal-Albert, Paloma,Faustino, Hlio,Gimeno, Ana,Asensio, Gregorio,Mascarenas, Jos L.,Lpez, Fernando
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Read Online
- Application of the SPE Method to Organic Electrochemistry-X. Behaviors of the Manganese Redox Couple Incorporated in Pt-Nafion and Their Mediatory Oxidation of Cinnamyl Alcohol to Cinnamaldehyd
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The electrochemical behavior of a manganese redox couple incorporated into an SPE (Solid Polymer Electrolyte) composite electrode using Nafion (Pt-Nafion) was examined as a mediator for electroorganic synthesis.The mediatory reaction of the redox couple w
- Ogumi, Zempachi,Mizoe, Toshiyuki,Zhen, Chen,Takehara, Zen-ichiro
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Read Online
- Sulfur-controlled and rhodium-catalyzed formal (3 + 3) transannulation of thioacyl carbenes with alk-2-enals and mechanistic insights
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A rhodium-catalyzed denitrogenative formal (3 + 3) transannulation of 1,2,3-thiadiazoles with alk-2-enals is achieved, producing 2,3-dihydrothiopyran-4-ones in moderate to excellent yields. An inverse KIE of 0.49 is obtained, suggesting the reversibility of the oxidative addition of thioacyl Rh(i) carbenes to alk-2-enals. The late-stage structural modifications of steroid compounds are realized. Moreover, our studies show that thioacyl carbenes have different reactivities to those of α-oxo and α-imino carbenes, and highlight the importance of heteroatoms in deciding the reactivities of heterovinyl carbenes.
- Wu, Qiuyue,Dong, Ziyang,Xu, Jiaxi,Yang, Zhanhui
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supporting information
p. 3173 - 3180
(2021/04/21)
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- 8π Electrocyclic Reaction of Phosphonate Derivatives: Access to Seven-Membered Cross-Conjugated Cyclic Trienes
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An anionic 8π electrocyclic reaction of 4-(diethoxyphosphoryl)-1,3,6-heptatriene derivatives was developed. Under the influence of a base, the substrate underwent deprotonation at the C5 position followed by the 8π electrocyclization of the resulting hept
- Saito, Hiroki,Kato, Ranmaru,Ikeuchi, Kazutada,Suzuki, Takahiro,Tanino, Keiji
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p. 9606 - 9610
(2021/12/17)
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- Tandem oxidation-dehydrogenation of (hetero)arylated primary alcohols via perruthenate catalysis
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Tandem oxidative-dehydrogenation of primary alcohols to give a,b-unsaturated aldehydes in one pot are rare transformations in organic synthesis, with only two methods currently available. Reported herein is a novel method using the bench-stable salt methyltriphenylphosphonium perruthenate (MTP3), and a new co-oxidant NEMO&middoPF6 (NEMO = N-ethyl-N-hydroxymorpholinium) which provides unsaturated aldehydes in low to moderate yields. The Ley-Griffith oxidation of (hetero)arylated primary alcohols with N-oxide co-oxidants NMO (NMO = N-methylmorpholine N-oxide)/NEMO, is expanded by addition of the N-oxide salt NEMO&middoPF6 to convert the intermediate saturated aldehyde into its unsaturated counterpart. The discovery, method development, reaction scope, and associated challenges of this method are highlighted. The conceptual value of late-stage dehydrogenation in natural product synthesis is demonstrated via the synthesis of a polyene scaffold related to auxarconjugatin B.
- Bettencourt, Christian J.,Chow, Sharon,Moore, Peter W.,Read, Christopher D.G.,Jiao, Yanxiao,Bakker, Jan Peter,Zhao, Sheng,Bernhardt, Paul V.,Williams, Craig M.
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p. 652 - 659
(2021/09/08)
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- Zwitterion-induced organic-metal hybrid catalysis in aerobic oxidation
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In many metal catalyses, the traditional strategy of removing chloride ions is to add silver salts via anion exchange to obtain highly active catalysts. Herein, we reported an alternative strategy of removing chloride anions from ruthenium trichloride using an organic [P+-N-] zwitterionic compound via multiple hydrogen bond interactions. The resultant organic-metal hybrid catalytic system has successfully been applied to the aerobic oxidation of alcohols, tetrahydroquinolines, and indolines under mild conditions. The performance of zwitterion is far superior to that of many other common Lewis bases or Br?nsted bases. Mechanistic studies revealed that the zwitterion triggers the dissociation of chloride from ruthenium trichloride via nonclassical hydrogen bond interaction. Preliminary studies show that the zwitterion is applicable to catalytic transfer semi-hydrogenation.
- Hu, Rong-Bin,Lam, Ying-Pong,Ng, Wing-Hin,Wong, Chun-Yuen,Yeung, Ying-Yeung
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p. 3498 - 3506
(2021/04/07)
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- Essential structural features of (2Z,4E)-5-phenylpenta-2,4-dienoic acid for inhibition of root gravitropism
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Previously, we found (2Z,4E)-5-phenylpenta-2,4-dienoic acid (ku-76) to be a selective inhibitor of root gravitropic bending of lettuce radicles at 5 μM, with no concomitant growth inhibition. Here, we describe a structure-activity relationship study of ku
- Shindo, Mitsuru,Makigawa, Saki,Matsumoto, Kenji,Iwata, Takayuki,Wasano, Naoya,Kano, Arihiro,Morita, Miyo Terao,Fujii, Yoshiharu
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- Customizing Photoredox Properties of PXX-based Dyes through Energy Level Rigid Shifts of Frontier Molecular Orbitals
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Here we describe the synthesis of electron-rich PXX derivatives in which the energy levels of the excited states have been rigidly shifted through the insertion of imide groups. This has allowed the development of a new series of oxygen-doped photoredox-active chromophores with improved oxidizing and reducing properties. Capitalizing on the dehalogenation of organic halides as a model reaction, we could investigate the photooxidative and photoreductive potential of these molecules in model chemical transformations. Depending on the substrate, solvent and dye the reaction mechanism can follow different paths. This prompted us to consider the first chemoselective transformation protocol, in which two different C?Br bonds could be chemoselectively reacted through the sequential photoactivation of two different colorants.
- Sciutto, Andrea,Fermi, Andrea,Folli, Andrea,Battisti, Tommaso,Beames, Joseph M.,Murphy, Damien M.,Bonifazi, Davide
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supporting information
p. 4382 - 4389
(2018/03/05)
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- Visible-Light-Promoted Nickel- and Organic-Dye-Cocatalyzed Formylation Reaction of Aryl Halides and Triflates and Vinyl Bromides with Diethoxyacetic Acid as a Formyl Equivalent
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A simple formylation reaction of aryl halides, aryl triflates, and vinyl bromides under synergistic nickel- and organic-dye-mediated photoredox catalysis is reported. Distinct from widely used palladium-catalyzed formylation processes, this reaction proceeds by a two-step mechanistic sequence involving initial in situ generation of the diethoxymethyl radical from diethoxyacetic acid by a 4CzIPN-mediated photoredox reaction. The formyl-radical equivalent then undergoes nickel-catalyzed substitution reactions with aryl halides and triflates and vinyl bromides to form the corresponding aldehyde products. Significantly, besides aryl bromides, less reactive aryl chlorides and triflates and vinyl halides serve as effective substrates for this process. Since the mild conditions involved in this reaction tolerate a plethora of functional groups, the process can be applied to the efficient preparation of diverse aromatic aldehydes.
- Huang, He,Li, Xiangmin,Yu, Chenguang,Zhang, Yueteng,Mariano, Patrick S.,Wang, Wei
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supporting information
p. 1500 - 1505
(2017/02/05)
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- Stereoselective organocatalytic oxidation of alcohols to enals: A homologation method to prepare polyenes
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A novel method for organocatalytic oxidation through oxidative enamine catalysis was developed with excellent compatibility for the direct syntheses of enals from simple saturated alcohols. By using this amine-catalyzed IBX-oxidation, a wide range of aromatic and aliphatic substituted enals were successfully generated in high yields and exclusively stereoselective E-geometry. Moreover, varying the solvents and/or the loading amounts of IBX allowed for the selective oxidation of alcohols and aldehydes. Importantly, the homologous application of this method provided a selective and efficient way of preparing various highly sensitive conjugated polyene frameworks, which are enriched in natural products.
- Chen, Xiaobei,Zhang, Yinan,Wan, Huixin,Wang, Wei,Zhang, Shilei
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p. 3532 - 3535
(2016/03/04)
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- Method for preparing Z-isomer by E-isomer of alpha, beta-nonsaturated carbonyl compound
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The invention provides a method for preparing a Z-isomer by an E-isomer of an alpha, beta-nonsaturated carbonyl compound. The method uses nitrogen-containing chiral binaphthol phosphoramidite to prepare a catalyst, under mild reaction condition, the E-isomer of the alpha, beta-nonsaturated carbonyl compound is efficiently conversed to the Z-isomer. The method is especially suitable for preparing neral through isomerization of partial geranial in a citral split residual material, the citral with mol ratio of the obtained geranial to neral being 1:1 can be reused for splitting the neral, raw material utilization rate is increased, and the cost is reduced.
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Paragraph 0050; 0051
(2017/04/29)
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- Br?nsted acid-catalyzed meyer-schuster rearrangement for the synthesis of α, β -unsaturated carbonyl compounds
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An efficient and simple protocol for the Meyer-Schuster rearrangement of propargyl alcohols into α,β-unsaturated carbonyl compounds has been developed using catalytic amounts of p-toluenesulfonic acid in 1,2-dichloroethane.
- Park, Jungmin,Yun, Jihee,Kim, Jaehyun,Jang, Dong-Jin,Park, Cheol Ho,Lee, Kooyeon
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p. 1924 - 1929
(2014/07/07)
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- Assembly of indenamine derivatives through in situ formed N-sulfonyliminium ion initiated cyclization
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An expedient route to structurally diverse indenamine derivatives through condensation of the readily accessible substituted cinnamylaldehydes and sulfonylamines under the catalysis of FeCl3 has been developed, featuring high efficiency in the generation of two bonds and one ring in a single-step and water as the only by-product. This journal is the Partner Organisations 2014.
- Fan, Xiaohui,Lv, Hao,Guan, Yong-Hong,Zhu, Hong-Bo,Cui, Xiao-Meng,Guo, Kun
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supporting information
p. 4119 - 4122
(2014/04/03)
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- Epoxide and hydroperoxide derived from naturally cinnamaldehyde and its Schiff base derivatives
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Thermal and photo epoxidation, photooxygenation reactions of cinnamaldehyde may be useful tool for the design of drugs to act as potent chemopreventation and anticancer agents. trans-Cinnamaldehyde was isolated from essential oil of cinnamon ( Cinnamonum verum). It was subjected to oxidation reactions either photochemically with hydrogen peroxide or thermally with 3-chloro-peroxybenzoic acid. Schiff base derivative was synthesized through condensation reaction with aniline. It subjected to photooxidation reaction in the presence of tetraphenylporphin as singlet oxygen sensitizer. photochemically oxidation reaction gave the corresponding epoxy derivative together with cis-isomerisation. Whereas, thermally oxidation reaction resulted the corresponding epoxy derivative together with cinnamic acid. In addition, photooxidation reaction of Schiff base derivative led to 1-phenyl-3-phenyliminopropen-1-yl hydroperoxide through endoperoxide derivative. The primary tested of hydroperoxide derivative showed a moderate degree of DNA degradation. trans-Cinnamaldehyde and its derivatives can act as antioxidants. They were trapped the reactive oxygen species (ROS) to give the intermediated epoxides and hydroperoxide derivatives, which could be alkylated or damage DNA, proteins and other biological species
- Elgendy, Eman M.,Khayyat, Suzan A.
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p. 6571 - 6574
(2015/02/19)
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- Redox-selective generation of aldehydes and H2 from alcohols under visible light
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Photosynthetic dehydrogenation: Potential usefulness of visible-light-induced dehydrogenation of alcohols in organic synthesis was demonstrated, in which aldehydes and H2 were afforded by using Ru/SrTiO3:Rh and water (see scheme). Water was essential for the reaction. High efficiency (TON: up to 15 400 based on Rh; H2 and aldehyde evenly generated) and high selectivity were achieved. Copyright
- Liu, Zijun,Caner, Joaquim,Kudo, Akihiko,Naka, Hiroshi,Saito, Susumu
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supporting information
p. 9452 - 9456
(2013/07/26)
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- Selective Oxidation of Benzylic and Allylic Alcohols Using Mn(OAc) 3/Catalytic 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone
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A practical, chemoselective oxidation of alcohols employing catalytic quantities of DDQ as the oxidant and Mn(OAc)3 as the co-oxidant is described. Electron-rich benzylic alcohols are oxidized efficiently to their corresponding carbonyls, but less electron-rich benzylic alcohols remain unchanged. Allylic alcohols are rapidly oxidized to their corresponding aldehyde or ketone counterparts in high yields. This protocol is operationally simple, employs an inexpensive source of Mn(OAc)3, has short reaction times, and exhibits a significant chemoselectivity favoring allylic alcohols over benzylic alcohols. This procedure also avoids the use of very large excesses of reagents and sometimes poor reproducibility that characterize previously developed reagents such as MnO2
- Cosner, Casey C.,Cabrera, Pablo J.,Byrd, Katherine M.,Adams Thomas, Asia M.,Helquist, Paul
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supporting information; experimental part
p. 2071 - 2073
(2011/06/19)
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- Stereoselective synthesis of (2E,4Z)-dienamides employing (triphenylphosphoranylidene)ketene
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The three-component reaction between ylide Ph3PCCO, amines and aldehydes is known to afford selectively (￡)-a,ssunsaturated amides. We applied a variant of this methodology to the preparation of (2B,4Z)-dienamides 11 utilizing the phosphonium s
- Pachali, Steffen,Hofmann, Christine,Rapp, Georg,Schobert, Rainer,Baro, Angelika,Frey, Wolfgang,Laschat, Sabine
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experimental part
p. 2828 - 2835
(2009/09/29)
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- Photochemical generation and structure of vinyl radicals
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Photolysis of a series of E or Z stereoisomeric α-R-substituted bromostyrenes (R = CH3, F or CN) in methanol yields E and/ or Z stereoisomeric styrenes, which stem from the corresponding vinyl radicals. The results show that the α-Me vinyl radical is a rapidly equilibrating, bent structure, while the α-F vinyl radical is a stable bent species, in agreement with earlier thermal results. The α-CN vinyl radical is assigned as a rapidly inverting bent and not a linear species from the stereochemical results as a function of temperature. Stereochemical data for the α-C(H)=O system in diethyl ether indicate a stable bent vinyl radical as product forming species. The conclusions are supported by quantum chemical computations. Wiley-VCH Verlag GmbH & Co. KGaA.
- Goumans, Theodorus P. M.,Van Alem, Kaj,Lodder, Gerrit
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p. 435 - 443
(2008/09/17)
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- Oxidoperoxidotungsten(VI) complexes with secondary hydroxamic acids: Synthesis, structure and catalytic uses in highly efficient, selective and ecologically benign oxidation of olefins, alcohols, sulfides and amines with H2O2 as a terminal oxidant
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The reaction of a solution of freshly precipitated WO3 in H 2O2 separately with the secondary hydroxamic acids N-benzoyl-N-phenylhydroxamic acid (BPHAH), N-benzoyl-Northo-tolylhydroxamic acid (BOTHAH), N-benzoyl-N-meta-tolylhydroxamic acid (BMTHAH), N-benzoyl-N-para- tolyl-hydroxamic acid (BPTHAH) and N-cinnamyl-N-phenylhy-droxamic acid (CPHAH) afforded [WO(O2)(BPHA)2] (1), [WO(O2)(BOTHA) 2] (2), [WO(O2)(BMTHA)2] (3), [WO(O 2)-(BPTHA)2] (4) and [WO(O2)(CPHA)2] (5), respectively. Aqueous tungstate solution, on reaction with all these hydroxamic acids, produced [W(O)2(hydroxamato)2] (6). The complexes show excellent catalytic functions in the oxidation of (a) olefins at room temperature in the presence of NaHCO3 as promoter, (b) alcohols, sulfides and amines, at reflux, with H2O2 as a terminal oxidant, yielding a high turnover number (TON), the highest being for olefin-to-epoxide conversion. An attempt to synthesize peroxide-rich complexes of the type PPh4[WO(O2)2(hydroxamato)] (7), for example PPh4[WO-(O2)2BMTHA] (7C), resulted in the isolation of PPh4[WO-(O2)2(C 6H5COO)] (8), which was probably obtained by the hydrolysis of coordinated BMTHA. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Maiti, Swarup K.,Dinda, Subhajit,Banerjee, Surajit,Mukherjee, Alok K.,Bhattacharyya, Ramgopal
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experimental part
p. 2038 - 2051
(2009/03/11)
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- Highly facile homogeneous epoxidation of olefins using oxo-diperoxo tungstate(VI) complex as catalyst, bicarbonate as co-catalyst and hydrogen peroxide as a terminal oxidant
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Addition of a dilute acetic acid solution of 8-quinolinol to an H 2O2 solution of freshly precipitated H2WO 4·2H2O furnishes a yellow adduct [WO(O 2)2·2QOH] 1 which, on crystallization from a suitable solvent, affords orange-yellow complex [WO(O2)(QO) 2] 2. When 2 reacts stoichiometrically with olefinic compounds in a 1:1 molar ratio, the respective olefins are epoxidized and 2 is converted to the orange-red [WO2(QO)2] 3. When 1 is treated with an excess of H2O2 (greater than 6 equiv.) and PPh4Cl, an anionic light yellow complex PPh4[WO(O2)2(QO)] 4 is obtained. 4 reacts with cyclopentene (a representative olefin) in a 1:1 molar ratio producing cyclopentene oxide and itself is converted to PPh 4[WO2(O2)(QO)] 5. If the above reaction is conducted at a 1:2 molar ratio (instead of 1:1) then 2 moles of the corresponding epoxide is formed and 4 is converted to PPh4[WO 3(QO)] 6. All these peroxo complexes have remarkable catalytic efficiencies in the epoxidation of olefinic compounds when used in tandem with NaHCO3 as co-catalyst and H2O2 as oxidant in a CH3CN medium at room temperature, the method being green and economical. The catalyst 4 under the above experimental conditions shows so far unmatched efficiency in epoxidizing a wide variety of olefinic substrates. the Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2006.
- Maiti, Swarup K.,Dinda, Subhajit,Gharah, Narottam,Bhattacharyya, Ramgopal
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p. 479 - 489
(2007/10/03)
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- Yb(OTf)3-TMSCl, a novel catalytic system in cross-aldol reactions
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A combination of Yb(OTf)3 and TMSCl influenced the outcome of cross-aldol reactions of cycloalkanones and benzaldehyde. Interestingly, reaction of cycloheptanone and cyclooctanone with aldehydes under the Yb(OTf)3- TMSCl reagent system provides 3-(2-oxocycloalkyl)-3- phenylpropanals in conjunction with the corresponding aldol products.
- Kagawa, Natsuko,Toyota, Masahiro,Ihara, Masataka
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p. 655 - 657
(2007/10/03)
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- Oxidation of alcohols using (NH4)2Cr 2O4 in the presence of Al(HSO4)3 and wet SiO2
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A mild and efficient method for the oxidation of alcohols by ammonium dichromate in the presence of Al(HSO4)3 and wet SiO 2 in solution or under solvent-free conditions is reported.
- Shirini, Farhad,Zolfigol, Mohammad A.,Abedini, Masoumeh,Salehi, Peyman
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p. 265 - 266
(2007/10/03)
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- An experimental (flash vacuum pyrolysis) and theoretical study of the tautomerism of pyrazolinones at high temperatures
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Flash vacuum pyrolysis experiments were carried out between 500 and 800°C on 3(5)-phenyl- and 3(5)-methylpyrazolinones and on 3(5)-methoxy-5(3)-phenylpyrazole. The origin of the isolated products (mainly indanone, hydroxyalkynes and α,β-unsaturated aldehydes) can be explained as arising from the hydroxy tautomers of pyrazolinones. Temperature effects on the tautomeric equilibrium of 1-phenyl-3-methylpyrazolinone in solution show that the percentage of the CH tautomer increases with the temperature. MP2 ab initio calculations on the model compound, pyrazolinone itself, have been used to rationalize these findings. The problem of the aromaticity of the four tautomers of pyrazolinone has been examined through Schleyer's NICS (nuclear independent chemical shifts) calculations.
- Yranzo, Gloria I.,Moyano, Elizabeth L.,Rozas, Isabel,Dardonville, Christophe,Elguero, Jose
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p. 211 - 216
(2007/10/03)
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- Photochemical generation of 'destabilized' vinyl cations
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Photolysis of α-formyl and α-cyano vinyl halides 3Z-X and 4E-X (X = Cl or Br) in methanol yields products resulting from the corresponding electronegatively substituted vinyl cations.
- Krijnen,Lodder
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p. 729 - 732
(2007/10/02)
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- Shape-selective isomerisation of α-acetylenic alcohols to α,β-ethylenic carbonyl compounds by vanadium-pillared montmorillonite catalyst
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A very simple, convenient method for an efficient shape-selective isomerisation of acyclic and aromatic α-acetylenic alcohols only, to the corresponding α,β-ethylenic carbonyl compounds, leaving the cyclic ones unreacted using catalytic amounts of vanadium-pillared montmorillonite catalyst, having -Si-O-V=0 groups with successful reusability is described.
- Choudary,Durga Prasad,Valli
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p. 7521 - 7522
(2007/10/02)
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- PREPARATION OF (E)-α,β-UNSATURATED AROMATIC ALDEHYDES BY HIGH STEREOSELECTIVE OLEFINFORMYLATION.
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Treatment of acetaldehyde N-ter-butylimine by two equivalents of LDA, followed by trimethylsilyl chloride trapping affords the α,α-disilylated imine; the latter reacts with aromatic aldehydes producing α,β-ethylenic aldehydes in excellent yields and with very high stereoselectivity in favour of the E isomer.
- Gaudemar, Marcel,Bellassoued, Moncef
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p. 349 - 352
(2007/10/02)
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- A Simple Route to α,β-Unsaturated Aldehydes from Prop-2-ynols
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2-Ynols can be isomerised stereoselectively to (2E)-enals with a ruthenium complex as catalyst.
- Ma, Dawei,Lu, Xiyan
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p. 890 - 891
(2007/10/02)
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- PREFERENTIAL FORMATION OF THE Z ISOMERS OF CINNAMALDEHYDES IN THE REARRANGEMENT OF ARYLETHYNYLCARBINOLS CATALYZED BY POLYVANADIOORGANOSILOXANES
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During the rearrangement of secondary and tertiary aryl(ethynyl)carbinols, catalyzed by polyvanadioorganosiloxanes, the thermodynamically less favorable Z isomers of the cinnamaldehydes are formed preferentially.It was shown that zero order in the initial carbinol and pseudofirst order in the catalyst are observed in the rearrangement.The activation parameters of the reaction, which confirm that the rearrangement takes place through a highly polar cyclic transition state, were determined.The dependence of the reaction rate on the structure of the initial carbinol is discussed.The Z-stereoselectivity of the rearrangement is explained by the presence of steric effects, which show up at the stage of the conversion of the intermediate allenyl vanadate into cinnamaldehyde.
- Gulyi, S. E.,Erman, M. B.,Novikov, N. A.,Aul'chenko, I. S.,Vol'pin, M. E.
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p. 715 - 721
(2007/10/02)
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- Reactions with Phosphine Alkylenes, 44. A Further Synthesis of (Z)-α,β-Unsaturated Aldehydes
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Reaction of phosphorus ylides 4, especially such with electron donating groups R, with the glyoxal semiacetal 5 leads Z-stereospecifically to the formation of the acetals 3, which can be cleaved to the (Z)-α,β-unsaturated aldehydes 6.
- Bestmann, Hans Juergen,Ermann, Peter
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p. 3264 - 3266
(2007/10/02)
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- Cumulated Ylides, XII. A Stereoselective Synthetic Method for (Z)-α,β-Unsaturated Aldehydes
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(2-Ethoxyvinyl)triphenylphosphonium bromide (5) is converted with sodium amide into the corresponding phosphaallenylide 6 which adds ethanol forming the ylide 7. 7 is also obtained by the reaction of 5 with sodium ethanolate.The Wittig reaction of 7 with aldehydes 2 proceeds with high (Z)-stereoselectivity to give (Z)-α,β-unsaturated acetals 8 which are cleaved under well defined conditions with p-toluenesulfonic acid or with wet silica gel to (Z)-α,β-unsaturated aldehydes 9.
- Bestmann, Hans Juergen,Roth, Kurt,Ettlinger, Manfred
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p. 161 - 171
(2007/10/02)
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- REINVESTIGATION OF THE GRIGNARD REACTIONS WITH FORMIC ACID. A CONVENIENT METHOD FOR PREPARATION OF ALDEHYDES
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Grignard reagents react with formic acid in tetrahydrofuran to produce aldehydes in relatively good yields.Various aldehydes such as alkyl, aryl, allyl, benzyl and vinyl aldehydes were prepared from the corresponding Grignard reagents.The reaction with vinyl Grignard reagents proceeded with retention of configuration.
- Sato, Fumie,Oguro, Kaoru,Watanabe, Hiroshi,Sato, Masao
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p. 2869 - 2872
(2007/10/02)
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