cas 16807-60-6, 3-METHOXY-2-CYCLOHEXEN-1-ONE

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Nickel-catalyzed regio- and stereoselective homo 1,4-dialkenylation of conjugated dienes
2,3-Dimethyl-1,3-butadiene and cyclic dienes react with β-iodoenones (RI: 3-Iodo-2-cyclohexen-1-one, 5,5-dimethyl-3-iodo-2-cyclohexen-1-one and 3-iodo-2-cyclopenten-1-one) in the presence of Zn and catalytic amount of NiBr2 to afford the corresponding homo 1,4-addition products in good yields. For 2,3-dimethyl-1,3-butadiene, only the products RCH2C(CH3)=C(CH3)CH2R with Z geometry were observed. For cyclic dienes, the products observed are RCHCH=CHCHR(CH2)(n)CH2 in which the two alkenyl substituents R are cis to each other.
Jou, Der-Ching,Hsiao, Tsung-Yu,Wu, Ming-Yuan,Kong, Kwang-Cheng,Cheng, Chien-Hong
p. 1041 - 1052
(1998)
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1H-IMIDAZO[4,5-H]QUINAZOLINE COMPOUND AS PROTEIN KINASE INHIBITOR
Provided is a 1H-imidazo[4,5-h]quinazoline compound of formula (I). The compound is a broad spectrum inhibitor having strong activity for cyclin-dependent kinase (CDK) and is applicable in treating cell proliferative disorder
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(2020/02/26)

Rapid and Multigram Synthesis of Vinylogous Esters under Continuous Flow: An Access to Transetherification and Reverse Reaction of Vinylogous Esters
An environmentally benign approach for the synthesis of vinylogous esters from 1,3-diketone and its reverse reaction under continuous-flow has been developed with alcohols in the presence of inexpensive Amberlyst-15 as a catalyst. This methodology is highly selective and general for a range of cyclic 1,3-dicarbonyl compounds which gives a library of linear alkylated and arylated vinylogous esters in good to excellent yield under solvent and metal free condition. Furthermore, the long-time experiment in a continuous-flow up to 40 h afforded 8.0 g of the vinylogous ester with turnover number (TON) = 28.6 and turnover frequency (TOF) = 0.715 h-1 using Amberlyst-15 as a catalyst. Furthermore, a continuous-flow sequential transetherification of vinylogous esters with various alcohols has been achieved in high yield. Reversibly, this vinylogous ester was deprotected or hydrolyzed into ketone using environmentally benign water as a solvent and Amberlyst-15 as a catalyst under continuous-flow process.
Mohanta, Nirmala,Chaudhari, Moreshwar B.,Digrawal, Naveen Kumar,Gnanaprakasam, Boopathy
p. 1034 - 1045
(2019/05/24)

Reversible chemoselective transetherification of vinylogous esters using Fe-catalyst under additive free conditions
An additive/Br?nsted acid/base free, highly efficient and chemoselective transetherification of electron deficient vinylogous esters and water mediated de-alkylation using an earth-abundant Fe-catalyst under very mild reaction conditions is described. This reaction is highly selective to primary alcohols over secondary alcohols, has good functional group tolerance, is scalable to gram scale and a purification free sequential transetherification in a continuous flow mode is demonstrated.
Parvathalu, Nenavath,Agalave, Sandip G.,Mohanta, Nirmala,Gnanaprakasam, Boopathy
p. 3258 - 3266
(2019/03/26)

Arene Trifunctionalization with Highly Fused Ring Systems through a Domino Aryne Nucleophilic and Diels–Alder Cascade
A convenient and efficient domino aryne process was developed under transition-metal-free conditions to generate a range of tetra- and pentacyclic ring systems. This transformation was realized via a 1,2-benzdiyne through a nucleophilic and Diels–Alder reaction cascade using styrene as the diene moiety. Three new chemical bonds, namely one C?N and two C?C bonds, and two benzofused rings could be constructed concomitantly, which was made possible by distinct chemoselective control at both the 1,2-aryne and 2,3-aryne stages. Moreover, in-depth studies were carried out on the domino aryne precursors and controlling the diastereoselectivity.
He, Jia,Jia, Zizi,Tan, Hongcheng,Luo, Xiaohua,Qiu, Dachuan,Shi, Jiarong,Xu, Hai,Li, Yang
supporting information
p. 18513 - 18518
(2019/11/19)

Lewis Acid Catalyzed Enantioselective Photochemical Rearrangements on the Singlet Potential Energy Surface
The oxadi-methane rearrangement of 2,4-cyclohexadienones to bicyclic ketones was found to proceed with high enantioselectivity (92-97% ee) in the presence of catalytic amounts of a chiral Lewis acid (15 examples, 52-80% yield). A notable feature of the transformation is the fact that it proceeds on the singlet hypersurface and that no triplet intermediates are involved. Rapid racemic background reactions were therefore avoided, and the catalyst loading could be kept low (10 mol %). Computational studies suggest that the enantioselectivity is determined within a Lewis acid bound singlet intermediate via a conical intersection. The utility of the method was demonstrated by a concise synthesis of the natural product trans-chrysanthemic acid.
Leverenz, Malte,Merten, Christian,Dreuw, Andreas,Bach, Thorsten
supporting information
p. 20053 - 20057
(2019/12/30)

Formation of meta-arylsulfanyl- and meta-(alkylsulfanyl)phenols from cyclohexane-1,3-diones
Reaction of cyclohexane-1,3-diones with TsCl/Et3N and treatment of the resulting 3-(tosyloxy)cyclohex-2-en-1-ones with aryl- or alkyl thiols and K2CO3 in MeCN gives 3-(arylsulfanyl)cyclohex-2-en-1-ones or 3-(alkylsulfanyl)cyclohex-2-en-1-ones, respectively. These compounds are easily brominated at C-2 by using NBS in MeCN; exposure to DBU in MeCN at room temperature then causes aromatization to afford meta-arylsulfanyl- and meta-(alkylsulfanyl)phenols.
Do Van Thanh, Nhan,Patra, Subrata,Clive, Derrick L.J.
p. 4343 - 4350
(2018/07/13)

AMINE-LINKED C3-GLUTARIMIDE DEGRONIMERS FOR TARGET PROTEIN DEGRADATION
This invention provides amine-linked C3-glutarimide Degronimers and Degrons for therapeutic applications as described further herein, and methods of use and compositions thereof as well as methods for their preparation.
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Page/Page column 478-479

(2017/12/01)

BENZO[B]THIOPHENE DERIVATIVES AND THEIR USE FOR THE INHIBITION OF FIBROBLAST GROWTH FACTOR RECEPTOR KINASES (FGFRS) FOR THE USE OF NEO- AND HYPERPLASIA THERAPIES
The present invention relates to benzo[b]thiophene derivatives of general formula (I) and pharmaceutically acceptable salts, solvates, hydrates, stereoisomeric and polymorphic forms thereof wherein R1 is selected from the group of hydrogen; hydroxyl; substituted or unsubstituted heterocyclyl; optionally substituted amino; X, Y and Z are selected independently from the followings: CH (methine), nitrogen; R2, R3, R4 and R5 may stand for e.g. hydrogen, halogen, hydroxyl, alkyl, alkenyl, alkynyl, alkoxy and amino. The invention also relates to the use of them as of medication, as well as pharmaceutical compositions containing at least one of them as pharmaceutically active agent(s) together with pharmaceutically acceptable carrier, excipient and/or diluent, especially for the inhibition Fibroblast Growth Factor Receptor kinases (FGFR's), e.g. for the treatment of cancer.
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Page/Page column 12; 25

(2017/09/27)

Synthesis of (±) debenzoyl analogs of norsampsones as potential anticancer agents
Synthesis of (±) debenzoyl analogs of norsampsones 1 and 2 is reported starting from commercially available 1,3-cyclohexadione in six steps with overall yields of 37% and 36%, respectively. Compounds 1 and 2 were tested for their anticancer activity and showed moderate anticancer activity against HeLa cell lines.
Jadhav, Amol R.,Thombal, Raju S.,Nigam, Preeti,Jadhav, Vrushali H.
p. 5235 - 5237
(2015/08/19)

Ionic liquid supported on magnetic nanoparticles as highly efficient and recyclable catalyst for the synthesis of β-keto enol ethers
A magnetically ionic liquid supported on γ-Fe2O 3 nanocatalyst (AlxCly-IL-SiO 2γ-Fe2O3) was synthesized and evaluated as a recoverable catalyst for the synthesis of β-keto enol ethers. The immobilized catalyst proved to be effective and provided the products in high to excellent yield at room temperature. Moreover, the catalyst could be easily recovered by magnetic separation and recycled for six times without significant loss of its catalytic activity.
Li, Pei-He,Li, Bao-Le,Hu, Hai-Chuan,Zhao, Xiao-Na,Zhang, Zhan-Hui
p. 118 - 122
(2014/01/17)

IMINO COMPOUNDS AS PROTECTING AGENTS AGAINST ULTRAVIOLET RADIATIONS
The present invention relates to compounds having the general Formula I: which absorb UV radiations and protect biological materials as well as non-biological materials from damaging exposure to UV radiations. The present invention also relates to formulations and compositions comprising such compounds for use in absorbing UV radiations and in protecting biological materials as well as non-biological materials against UV radiations.
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Page/Page column 36

(2014/01/08)

Cyclometalation of anthyridine-based ligands with dirhodium acetates: Structure and catalytic activity
Coordination of 2,8-Ar2-5-phenylanthyridines (Ar = 2-thienyl, 1a; Ar = 2-ClC6H4-, 1b) with dirhodium tetraacetate yielded the cyclometalated complexes [Rh2(OAc)3(metalated- 1a)] (3a) and [Rh2(OAc)3(metalated-1b)] (3b), respectively. Under acidic conditions, cleavage of the Rh-C bond in 3a,b took place to give the corresponding coordination complexes 4a,b. Treatment of 3a,b with PPh3 led to the phosphine-cyclometalated species [Rh 2(OAc)2{P,C-(C6H4)PPh 2}(metalated-1a)] (5a) and [Rh2(OAc)2{P,C- (C6H4)PPh2}(metalated-1b)] (5b), respectively. These new dirhodium complexes have been structurally characterized by NMR spectroscopy, and some representative compounds were also analyzed by X-ray methods. The use of these newly prepared dirhodium complexes as catalysts for the allylic oxidation of cyclohexenes was investigated.
Huang, Da-Wei,Lo, Ying-Hao,Liu, Yi-Hung,Peng, Shie-Ming,Liu, Shiuh-Tzung
p. 4009 - 4015
(2013/08/23)

Cyclization of 5-hexynoic acid to 3-alkoxy-2-cyclohexenones
The one-pot cyclization of 5-hexynoic acid to produce 3-alkoxy-2- cyclohexenones proceeds in good yields (58-90%). 3-Hexynoic acid was converted to its acyl chloride with the aid of oxalyl chloride and was cyclized to 3-chloro-2-cyclohexenone upon addition of indium(III) chloride. Subsequent addition of alcohol nucleophiles led to the desired 3-alkoxy-2-cyclohexenones.
Hylden, Anne T.,Uzelac, Eric J.,Ostojic, Zeljko,Wu, Ting-Ting,Sacry, Keely L.,Sacry, Krista L.,Xi, Lin,Jones, T. Nicholas
experimental part
p. 1323 - 1326
(2011/11/06)

Asymmetric synthesis of O-protected acyloins using enoate reductases: Stereochemical control through protecting group modification
O-Protected cyclic acyloins were obtained in nonracemic form through asymmetric bioreduction of α,β-unsaturated alkoxy ketones by using 11 different enoate reductases from the "Old Yellow Enzyme" family. The stereochemical outcome of the biotransformation could be switched by variation of the O-protecting group or by the ring size of the substrate, which allows access to both stereoisomers in up to >97 % ee Whereas α-alkoxy enones were readily accepted as substrates, β-analogs were not converted. Overall, α-alkoxy enones represent a novel type of substrate for flavin-dependent ene-reductases. Copyright
Winkler, Christoph K.,Stueckler, Clemens,Mueller, Nicole J.,Pressnitz, Desiree,Faber, Kurt
supporting information; experimental part
p. 6354 - 6358
(2011/02/24)

Pyrrolopyrazinyl Urea Kinase Inhibitors
The present invention relates to the use of novel pyrrolopyrazinyl urea derivatives of Formula I, wherein the variables R1, R2, R3, R4, and R5 are defined as described herein, which inhibit JAK and are useful for the treatment of auto-immune and inflammatory diseases.
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Page/Page column 43

(2010/06/19)

Titanium(III) chloride mediated synthesis of furan derivatives: Synthesis of (±)-evodone
Titanocene(III) chloride (Cp2TiCl) mediated one-pot synthesis of furan derivatives has been accomplished. This radical method has been applied for the synthesis of a furanomonoterpene, evodone. Ti(III) species was prepared in situ from commercially available titanocene dichloride (Cp2TiCl 2) and zinc dust in THF. Indian Academy of Sciences.
Mandal,Paira,Roy
scheme or table
p. 423 - 426
(2010/12/25)

Divergent reactivity in tandem reduction - Michael ring closures of five- and six-membered cyclic enones
(Chemical Equation Presented) In this study, methyl (±)-1-(2- nitrobenzyl)-4-oxo-2-cyclohexene-1-carboxylate and methyl (±)-(2- nitrobenzyl)-4-oxo-2-cyclopentene-1-carboxylate were prepared and subjected to reductive cyclization under dissolving metal conditions. The two reactants showed divergent behavior with the six-ring substrate reacting at the ester carbonyl and the five-ring substrate closing on the enone double bond. The difference in reactivity is attributed to the conformational flexibility, relative reactivity, and steric environment of C4-substituted six- and five-membered cyclic enones.
Bunce, Richard A.,Nammalwar, Baskar,Slaughter, LeGrande M.
experimental part
p. 854 - 860
(2009/12/24)

Iron(III) tosylate in the preparation of dimethyl and diethyl acetals from ketones and β-keto enol ethers from cyclic β-diketones
An efficient method for conversion of ketones to their corresponding dimethyl and diethyl acetals and of cyclic β-diketones into β-keto enol ethers using Fe(OTs)3 as a catalyst is described. Copyright Taylor & Francis Group, LLC.
Mansilla, Horacio,Afonso, Maria M.
p. 2607 - 2618
(2008/12/22)

3'-ALKOXY SPIROCYCLIC TETRAMIC AND TETRONIC ACIDS
The invention relates to novel 3'-alkoxy spirocyclic tetramic and tetronic acids of formula (I), wherein A, B, D, Q1, Q2, G, W, X, Y and Z are as defined in the description, to several methods and intermediate products for the production and the use thereof in the form of pesticides and/or herbicides and/or microbicides, to selective herbicide agents, 3'-alkoxy spirocyclic tetramic and tetronic acids and to at least one compound which improves cultivated plants compatibility.
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Page/Page column 166

(2008/06/13)

Cerium(IV) ammonium nitrate-catalyzed synthesis of β-keto enol ethers from cyclic β-diketones and their deprotection
A mild and efficient method for etherification of cyclic β-diketones with alcohols has been developed using a catalytic amount of cerium(IV) ammonium nitrate at room temperature to afford the corresponding β-keto enol ethers in good to excellent yields. The deprotections of enol ethers in water-acetonitrile (1:1) using a catalytic amount (10 mol %) of cerium(IV) ammonium nitrate have also been achieved. Copyright
Banerjee, Biplab,Mandal, Samir Kumar,Roy, Subhas Chandra
p. 16 - 17
(2007/10/03)

Ytterbium triflate catalyzed synthesis of β-keto enol ethers
β-Keto enol ethers have been synthesized in very good yield in solvent-free conditions from differently substituted alcohols and β-diketones in the presence of Yb(OTf)3 as catalyst. The method is applicable to both cyclic and acyclic β-diketones with only slight differences in the experimental procedure.
Curini, Massimo,Epifano, Francesco,Genovese, Salvatore
p. 4697 - 4700
(2007/10/03)

An efficient conversion of β-diketones into β-keto enol ethers with P2O5/SiO2 under solvent-free conditions
P2O5/SiO2 was found to be an efficient reagent for converting cyclic-β-diketones into their corresponding β-keto enol ethers at room temperature under solvent-free conditions.
Cui, Zhen-Shui,Zhang, Zhan-Hui,Liu, Shu-Fen
p. 390 - 392
(2007/10/03)

High-pressure-promoted uncatalyzed ketalization of ketones and oxy-Michael/ketalization of conjugated enones
A new practical method for ketalization or oxy-Michael/ketalization was developed using the high-pressure-promoted condensation of ketones or α,β-unsaturated ketones with alcohols in the presence of trialkyl orthoformates as water scavengers. Georg Thieme Verlag Stuttgart.
Kumamoto, Koji,Ichikawa, Yoshiyasu,Kotsuki, Hiyoshizo
p. 2254 - 2256
(2007/10/03)

B(C6F5)3-catalyzed synthesis of β-keto enol ethers from β-diketones
Efficient and practical synthesis of β-keto enol ethers from diketones catalyzed by B(C6F5)3 at room temperature has been described. Georg Thieme Verlag Stuttgart.
Chandrasekhar,Srinivasa Rao,Ramakrishna Reddy
p. 1471 - 1473
(2007/10/03)

Microwave assisted rapid synthesis of 3-alkoxy-2-cyclohexen-1-ones from 1,3-cyclohexanedione
Synthesis of 3-alkoxy-2-cyclohexen-1-ones from 1,3-cyclohexanedione with various alcohols has been achieved under microwave irradiation conditions within 7 min.
Murugan,Reddy
p. 1512 - 1514
(2007/10/03)

Solvent free rapid synthesis of 3-alkoxycyclohex-2-en-1-one from 1,3-cyclohexanedione promoted by indium(in) chloride/silica gel
A convenient and environmentally friendly method for the synthesis of 3-alkoxycyclohex-2-en-1-one 1 from cyclohexane-1,3-dioneonthe surface of silica gel impregnated with indium(III) chloride under microwave irradiation without any solvent has been reported CSIRO 2005.
Murugan,Kamakshi,Reddy, Boreddy S. R.
p. 228 - 230
(2008/02/04)

The total synthesis of coleophomones B, C, and D
Members of the coleophomone family of natural products all possess several intriguing and challenging architectural features, as well as exhibit unusual biological activity. They, therefore, constitute attractive targets for synthesis. In this Article, we describe the total synthesis of coleophomones B (2), C (3), and D (4). The highly strained and congested 11-membered macrocycle of coleophomones B (2) and C (3) was constructed using an impressive olefin metathesis reaction. Furthermore, both of the requisite geometric isomers of the Δ within the macrocycle could be accessed from a common precursor, facilitating a divergence that lent the coleophomone B (2)/C (3) synthesis an unusually high degree of efficiency. The synthesis of coleophomone D (4) confirmed that it exists as a dynamic mixture of isomeric forms with a different aromatic substitution pattern from the other family members.
Nicolaou,Montagnon, Tamsyn,Vassilikogiannakis, Georgios,Mathison, Casey J. N.
p. 8872 - 8888
(2007/10/03)

Iodine-catalyzed synthesis of β-keto enol ethers
The use of iodine, as a catalyst for the synthesis of β-keto enol ethers at room temperature is reported. The use of iodine, as a catalyst for the synthesis of β-keto enol ethers at room temperature is reported.
Bhosale, Rajesh S.,Bhosale, Sidhanath V.,Bhosale, Sheshanath V.,Wang, Tianyu,Zubaidha
p. 7187 - 7188
(2007/10/03)

Synthesis and spectroscopic characterization of [5-13C]- and [6-13C]ubiquinone-10 for studies of bacterial photosynthetic reaction centers
This paper presents the synthesis and characterization by mass spectrometry and NMR spectroscopy of [2-13C]- and [3-13C]ubiquinone-0 and of [5-13C]- and [6-13C]ubiquinone-10. A scheme based on the synthetic approach to [5-13C]ubiquinone-10 has been worked out for the synthesis of ubiquinones 13C-labeled at any individual position and at every combination of positions in the quinone ring. The [5-13C]- and [6-13C]ubiquinone-10 isotopomers were incorporated into the QA-site of the photosynthetic reaction center of Rhodobacter sphaeroides R-26. Magic angle spinning NMR subsequently revealed an unperturbed 6-position, while the signal of the 5-position was absent. These results corroborate the recently reported detection of an asymmetric binding of QA with a dynamic perturbation involving the 4-carbonyl functionality.
Boers, Rutger B.,Gast, Peter,Hoff, Arnold J.,De Groot, Huub J. M.,Lugtenburg, Johan
p. 189 - 202
(2007/10/03)

Synthesis and spectroscopic characterization of [1′-14C]ubiquinone-2, [1′-14C]-5-demethoxy-5-hydroxyubiquinone-2, and [1′-14C]-5-demethoxyubiquinone-2
[1′-14C]Ubiquinone-2, [1′-14C]-5-demethoxy-5-hydroxyubiquinone-2, and [1′-14C]-5-demethoxyubiquinone-2 have been synthesised from [1-14C]acetic acid. A common feature of these benzoquinones is the isoprenoid chain, and the 14C-label has therefore been incorporated in this isoprenoid. The coupling of the different quinone head groups and the isoprenoid chain is the last step in the total synthesis, to prevent unnecessary loss of the labelled material during synthesis. The products have been characterised by mass spectrometry, 1H NMR and 13C NMR.
Van Der Klei, Anita,De Jong, Robertus L. P.,Lugtenburg, Johan,Tielens, Aloysius G. M.
p. 3015 - 3023
(2007/10/03)

Towards a synthesis of epothilone A: Asymmetric synthesis of C(1)-C(6) and C(7)-C(15) fragments
The asymmetric synthesis of protected C(1)-C(6) and C(7)-C(15) fragments of epothilone A starting from 1,3-cyclohexanedione and methyl L-hydroxy propionate, respectively, is described.
Chandrasekhar,Reddy
p. 261 - 268
(2007/10/03)

Mild acetalisation of mono and dicarbonyl compounds catalysed by titanium tetrachloride. Facile synthesis of β-keto enol ethers
The use of TiCl4, as a catalyst for the acetalisation, at room temperature, of carbonyl compounds is reported. Cyclic ketones and cyclic 1,4-diketones easily afford dimethyl acetals, but cyclic 1,3-diketones give β-keto enol ethers. Additionally, aryl ketones and acyclic ketones failed to react. β-keto aldehydes can be monoprotected either as β-keto enol ethers or β-keto dimethyl acetals depending on the reaction time and catalyst amount. Some mechanistic features are accounted for.
Clerici, Angelo,Pastori, Nadia,Porta, Ombretta
p. 217 - 225
(2007/10/03)

Reaction of Phosphonate-Stabilized Carbanions with Cyclic Enones Bearing a β-Leaving Group
Reaction between α-lithiated alkylphosphonic esters and α,β-unsaturated cyclopentenones and cyclohexenones carrying a heteroatom substituent Y in the β-position was studied.Complete chemoselectivity was observed as a function of substituent Y.For Y = OMe exclusive addition-elimination at the β-carbon was observed, yielding α,β-unsaturated δ-ketophosphonates.The β-chloro-substituted substrates (Y = Cl) derived from cyclohexenone reacted exclusively at the carbonyl carbon, yielding (2-hydroxyalkyl)phosphonates with the retained chlorovinyl function.The alcohols, depending on the conditions, could be dehydrated to two different products.The reaction of 3-chlorocyclopent-2-en-1-one with diethyl (lithiomethyl)phosphonate occured at the β-carbon, but the ketophosphonate product was isolated in a stable enolic form.
Mphahlele, Malose J.,Modro, Tomasz A.
p. 8236 - 8240
(2007/10/03)

Synthesis and Binding of Simple Neocarzinostatin Chromophore Analogues to the Apoprotein
Synthetic analogues (3-5, 8-10) of neocarzinostatin chromophore (1) are found to bind to the apoprotein with high affinity.Their binding energies suggest that the naphthoate moiety of 1 is essential for the binding, and that the C5-CH3 and C7-OCH3 groups are necessary for the high affinity.
Takahashi, Kazunobu,Tanaka, Toshiyuki,Suzuki, Toshio,Hirama, Masahiro
p. 1327 - 1340
(2007/10/02)

Microbiological synthesis of optically active (2R,3S)-2,3-deuteriocyclohexan-1-ones and (2R,3S)-2methyl-3-deuteriocyclohexan-1-one. Enantiospecific anti-addition of hydrogen to the double bond of cyclohex-2-en-1-ones
Addition of hydrogen of the double bond of cyclohexenones during microbiological reduction by Beauveria sulfurescens gives the trans product in high yield (90%) resulting from anti-addition to the si face on C-2 and the re face on C-3.
Dauphin,Gourcy,Veschambre
p. 595 - 598
(2007/10/02)

Aromatization of 1,4-Cyclohexadienes with Tetracyanoethylene: A Case of Varying Mechanisms
The aromatization of 1,4-cyclohexadiene and four alkyl-substituted 1,4-cyclohexadienes with tetracyanoethylene was examined and found in four of five cases to involve two competing mechanisms.Most of each reaction proceeded by concerted ene addition followed by breakdown of the ene product, probably heterolytically.Rate constans for diene reaction were determined in acetonitrile-d3 and p-dioxane-d8.Adducts were isolated in three cases and rate constants for adduct breakdown determined for isolated compounds.Where the adduct could be observed but not isolated, a constant was calculated through computer simulation of the rate data.The minor mechanism competing with the ene addition displayed not detectable intermediates and seemed most consistent with electron-proton-electron-proton or electron-proton-hydrogen-atom transfer.Total reaction rate varied by a factor of over 4 * 105, yet with one exception, the ratio of the two pathways varied very little.One possible explaonation for this, the presence of a common rate determining step preceding any hydrogen transfer (such as SET) was ruled out by the finding of a large primary isotope effect for hexadeuterio-1,4-cyclohexadiene disappearance (kH/kD = 5.2).With one diene, 3,3-dimethyl-1,4-cyclohexadiene, the otherwise minor mechanism became the sole one, as the adduct formed was clearly not a concerted ene adduct.However, in this case aromatization also required a 1,2 methyl shift, and the fact that quantitative collapse to an adduct, without rearrangement, occured instead ruled out a simple cation intermediate from hydride transfer.A reversible electron transfer therefore seems the likeliest first step for the minor mechanism.
Jacobson, Barry M.,Soteropoulos, Patricia,Bahadori, Sheila
p. 3247 - 3255
(2007/10/02)

Experiments on the total synthesis of lysolipid I. Part II. Michael addition of 1,3-cyclohexanedione to quinone acetals
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Duthaler,Wegmann
p. 1755 - 1766
(2007/10/02)

Tricarbonylcyclohexadienyliron Complexes as Aryl Equivalents: A Formal Synthesis of (+/-)-O-Methyljoubertiamine
The use of tricarbonyl(4-methoxycyclohexadienyl)iron hexafluorophosphate 1b as a synthetic equivalent of the p-anisyl cation for a formal synthesis of (+/-)-O-methyljoubertiamine is described.
Pearson, Anthony J.,Richards, Ian C.,Gardner, Derek V.
p. 3887 - 3891
(2007/10/02)

REACTIVITE PHOTOCHIMIQUE DES DIALKYLAMINO-2 CYCLOHEXENE-2 ONES ET DES SELS D'AMMONIUM CORRESPONDANTS
Photolysis of 2-dialkylamino-2-cyclohexenones leads to α-ketoazetidines.The reactivity of 3-methyl-2-dialkylamino-2-cyclohexenones and the effect of the nature of the dialkylamino groups on the photocyclization are discussed.Photolysis of the corresponding ammonium salts in hydroxylic solvents led only to adduct formation.
Arnould, J. C.,Cossy, J.,Pete, J. P.
p. 1921 - 1926
(2007/10/02)

Studies on Lactam Acetals: Part V - Use in N-, O- and S-Alkylations and Esterification
The utility of 2,2-dimethoxy-1-methylpyrrolidine as a reagent for facile N-, O-, S-alkylations and esterification, or both simultaneously, of a wide variety of substrates has been demonstrated.
Singh, Jujhar,Nigam, M. B.,Sardana, Vinod,Jain, Padam C.,Anand, Nitya
p. 596 - 597
(2007/10/02)