bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photochemical Reactions. Part 67. photochemistry of saturated aliphatic and cyclic β‐keto sulfoxides (CαS)‐ and α‐cleavage – A new case of photostereomutation
Authors: Ganter C. , Moser J.‐F. 
Published: December 2004

AbstractThe photochemical behaviour of saturated aliphatic (2, 4, and 5) and bicyclic (18 and 19) β‐keto sulfoxides has been studied. Photostereomutation of the sulfoxide group was observed on irradiation of 4a, 4b, 18, and 19. Most likely an internal energy transfer from the excited carbonyl to the sulfoxide group is operating on direct irradiation of such compounds.Prolonged photolysis of an aliphatic β‐keto sulfoxide, which is nonalkylated a t the α‐carbon (2), yielded a product due to preferential (Cα‐S)‐cleavage (24). Mono‐ (4) and dialkylated‐ (5,6, and 8)analogues primarily afforded products due to α‐cleavage (26–31 and 32). The carboxylic acid S‐methylesters (26–31) were exclusively formed by an intermolecular path. Prolonged irradiation of the bicyclic β‐keto sulfoxides 18 and 19 favored the formation of a desulfurized compound 34 due to initial (Cα‐S)‐cleavage.
Molecules and Crystals, 1926–1970
Authors: Robertson J. M. 
Published: December 2004

AbstractSome features in the history and development of the X‐ray crystallography of organic molecules are described, from the simple but fundamental structures of the 1920's and 1930's to the complex biological structures of today. The most important developments were probably the introduction of phase determining methods based on the use of heavy atoms, and the invention of the electronic digital computer.
Anil‐Synthese. 4. Mitteilung. Über die Basen‐katalysierte Umsetzung von 4‐Methyl‐azobenzol‐Derivaten mit Anilen aromatischer Aldehyde
Authors: Weickhardt B. , Siegrist A. E. 
Published: December 2004

Abstract4‐Methyl‐azobenzol‐Derivate ohne elektronenanziehende Substituenten und ohne Gruppen, die mit Basen Salze bilden, werden mit Anilen aromatischer Aldehyde in Dimethylformamid in Gegenwart von Kaliumhydroxid oder Kalium‐t‐butylat zu Styryl‐Derivaten umgesetzt («Anil‐Synthese»). Bei Anwesenheit von elektronenanziehenden Gruppen dagegen werden die 4‐Methyl‐azobenzol‐Derivate zu symmetrischen Dibenzyl‐ bzw. Stilben‐Derivaten oxydiert. Mit 4‐Benzyl‐azobenzol‐Derivaten gelingt die Anil‐Synthese nur bei gleichzeitiger Anwesenheit von Elektronen‐Donatoren in 4′‐Stellung des Azobenzols.
Stoffwechselprodukte von Mikroorganismen. 98. Mitteilung. Phosphinothricin und Phosphinothricyl‐Alanyl‐Alanin
Authors: Bayer E. , Gugel K. H. , Hägele K. , Hagenmaier H. , Jessipow S. , König W. A. , Zähner H. 
Published: December 2004

AbstractFrom cultures of Streptomyces viridochromogenes a new antibiotic, phosphinothricylalanyl‐alanine, has been isolated. The new amino acid phosphinothricin is 2‐amino‐4‐methyl‐phosphino‐butyric acid, its structure is confirmed by synthesis.The tripeptide is highly active against Gram‐positive and Gram‐negative bacteria and against the fungus Botrytis cinerea. Phosphinothricin is an active glutamine synthetase inhibitor.
The Acidity of Malondialdehyde and the Stability of its Complexes with Nickel(II) and Copper(II)
Authors: Osman M. M. 
Published: December 2004

AbstractThe acidity of malondialdehyde as well as the stability of its 1 :1‐complexes with NiII and CuII have been determined (Table). In comparison with the enolates of aliphatic β‐dike‐tones the anion C3H3O2− has not only a strikingly reduced basicity, but is also a grossly inferior ligand for metal cations.
Synthesis of δ‐Lactones from Glutaraldehyde
Authors: Rosenberger M. , Andrews D. , DiMaria F. , Duggan A. J. , Saucy G. 
Published: December 2004

AbstractA novel and general synthesis of δ‐lactones from glutaraldehyde is described. The dialdehyde is first reacted with an alkyl or substituted alkyl Grignard reagent to afford a δ‐hydroxyaldehyde in good yield. These aldehydes exist preferentially in the cyclic hemiacetal form (δ‐lactols). Oxidation of the latter compounds to give δ‐lactones is readily achieved with silver oxide or bromine. The δ‐lactols and δ‐lactones serve as intermediates for the total synthesis of steroids.
13C‐kernresonanzspektroskopische Untersuchung der Wechselwirkung von Makrotetrolid‐Antibioticamit Na+, K+, Rb+, Cs+, NH4+ und Ba2+
Authors: Pretsch E. , Vašák M. , Simon W. 
Published: December 2004

AbstractThe 13C NMR. spectra of nonaction have been recorded at 22.6 MHz. Additivityrules, chemical shift reagents and spectra of model compounds enabled a full assignment of the lines to be made. A comparison of the spectra of the nonactin complexes with Na+, K+, Rb+, Cs+, NH4+ and Ba2+ showed that no H‐bridges between NH4+ and the nonactin carbonyls exist. This is corroborated by the infrared spectra of the complexes.
Poly‐aminoalkylation d'amines, en solution aqueuse ou aquo‐alcoolique, à l'aide d'acides amino‐2‐alkylsulfuriques
Authors: Rabinowitz Joseph 
Published: December 2004

AbstractAlkali stable primary and secondary amines (of the types H2NCH2CH2OPO3Na2, H2NCH2COONa, H2NCH2CH2OH, H3CNHCH2CH2OH, etc.) heated with n mole‐equiv. of a 2‐amino‐1‐alkylsulfuric acid in aqueous solution, in the presence of 2 n mole‐equiv. of NaOH, giverise to a mixture of poly‐aminoalkylated derivatives with an average degree of aminoalkylation close to n. If the amine is insoluble in water, a mixture of water+an alcohol can be used. In the case of N‐methylaminoethylsulfuric acid, the reaction is carried out in a closed vessel since the intermediate N‐methylaziridine boils at 27,5° under normal pressure.These polyaminoalkyl derivatives are capable of being acylated, alkylated, and cyclized. Some stearylated products are described.
Steroids and sex hormones. Part 245. Partial synthesis of batrachotoxinin A. Preliminary communication
Authors: Imhof R. , Gössinger Miss E. , Graf W. , Berner H. , Berner‐Fenz Mrs. L. , Wehrli H. 
Published: December 2004

AbstractIm Rahmen der vorliegenden Mitteilung wird über den erstmaligen partialsynthetischen Aufbau des Steroidalkaloids Batrachotoxinin A (23) [4] berichtet. Als Ausgangsmaterial der Synthese diente das 20‐Oxo‐pregnan‐Derivat 2, das von uns bereits früher [3] aus dem 18,20‐Lacton 1 [2] dargestellt worden ist.
Arbeiten über Phosphorsäure‐ und Thiophosphorsäureester mit einem heterocyclischen Substituenten. 4. Mitteilung. 3‐Isopropyliden‐dithiocarbazinsäure‐alkylester und deren Ringschluss zu 5‐Alkylthio‐1,3,4‐thiadiazol‐2(3H)‐onen
Authors: Rüfenacht K. 
Published: December 2004

AbstractImpurities in crude oily dithiocarbazic acid (2′‐methoxy)‐ethyl ester causing troubles in the ring closure to 5‐(2′‐methoxy‐ethylthio)‐1,3,4‐thiadiazol‐2(3H)‐one and in succeeding reactions are eliminated by using the crystalline 3‐isopropylidene‐dithiocarbazic acid (2′‐methoxy)‐ethyl ester, which can be obtained directly by alkylation of potassium dithiocarbazate with 2‐methoxy‐ethyl bromide in presence of acetone. By the action of phosgene followed by that of water, the isopropylidene compound yields the oily 5‐(2′‐methoxy‐ethylthio)‐1,3,4‐thiadiazol‐2(3H)‐one by splitting off the isopropylidene group and by ring closure in one single step.
The Photochemical Methylenecyclopropane Rearrangement of Feist's Ester
Authors: Kagan Jacques 
Published: December 2004

AbstractIn contrast to the thermal rearrangement, the photochemically induced methylenecyclopropane rearrangement of diethyl trans‐methylenecyclopropane‐2,3‐dicarboxylate (I) and of ethyl ethoxycarbonylcyclopropylideneacetate (syn or anti) produced diethyl cis‐methylenecyclopropane‐2,3‐dicarboxylate. A true photoequilibrium was not observed.
Glykoside von Marsdenia erecta R. Br. 2. Mitteilung: Versuche zur Strukturbestimmung der Genine. Glykoside und Aglykone, 330. Mitteilung
Authors: Saner A. , Stöckel K. , Reichstein T. 
Published: December 2004

AbstractStructures for the genins of the ester glycosides of Marsdenia erecta are suggested. They are based on the behaviour in alkaline hydrolysis of these ester glycosides, their NMR. and mass spectra and ORD. data. All genins are derived from three acyl‐free pregnane derivatives, i.e. drevogenin‐P (1), 17 β‐marsdenin (3) and marsectohexol (7). The structure of 1 is known, 3 and 7 are new compounds, i.e. 3 = 3β,8β,11α,12β,14β‐pentahydroxy‐Δ5‐pregnen‐20‐one and 7 = 3β,8β,11α,12β,14β,20ξ‐hexahydroxy‐Δ5‐pregnene.Formulae 13–17 were attributed to the acyl‐genins A‐1, A‐2, A‐3, A‐4 and A‐5, but only two of them were pure compounds, i.e. acyl‐genin A‐3 = 11,12‐di‐O‐tiglyl‐17β‐marsdenin (15) and acyl‐genin A‐5 = 11,12‐di‐O‐acetyl‐marsectohexoi (17). Acyl‐genin A‐1 is a mixture of the two esters 13a + 13b derived from drevogenin‐P, and similarly acyl‐genin A‐2 is a mixture of the esters 14a + 14b derived from 17β‐marsdenin. The poorly characterised acyl‐genin A‐4 is most probably a mixture of the esters 16a + 16b, also derived from 17β‐marsdenin.
Untersuchungen zur Physisorption und Chemisorption von Wasser auf Zinkoxid‐Oberflächen
Authors: Mattmann G. , Oswald H. R. , Schweizer F. 
Published: December 2004

AbstractThe investigation of different zinc oxide samples by means of thermogravimetry and infrared spectroscopy has shown that the surface of the samples is covered by an approximately monoatomic layer of hydroxide groups. Furthermore, varying amounts of carbonate groups are found which are due to the presence of zinc hydroxide carbonate II [Zn5(OH)6(CO3)2]. Below relative water vapour pressures of p/p0 = 0.2 (25°C), two hydrogen bridges connect one physisorbed water molecule with two chemisorbed surface hydroxide groups. In addition, about the same amount of water is physically adsorbed between vapour pressures of p/p0 0.2 and 0.8. At still higher relative humidity, a multimolecular layer is built up which reaches a thickness of about 200 water molecules at p/p0 = 1.0.All samples show in the v‐OH region of the IR. spectrum a broad absorption with four bands, A, B, C, and D. The position of the bands and the change of their intensities when rising the temperature of the samples up to 600°C indicate that both bands of longer wave lengths, C and D, arise from physically adsorbed water molecules, while the bands A and B are due to hydroxide groups located on the crystallographic faces (0001) and (0001), respectively.
Dérivés C‐glycosyliques. VII. Synthèse et réactions de nitrones dérivées de sucres. Communication préliminaire
Authors: Tronchet J. M. J. , Mihaly Melle E. 
Published: December 2004

AbstractThe syntheses of three types of sugar nitrones (aldonitrone, ketonitrone and α‐β unsaturated aldonitrone) are described. On 1,3‐dipolar cycloaddition with phenylacetylene, the aldonitrone gave two Δ4‐isoxazolines epimeric at the new asymetric carbon, while the same reaction on the ketonitrone led to a spiro‐Δ4‐isoxazoline. The reaction of these nitrones with carbon nucleophiles like phenylethynylmagnesium bromide constitutes a novel chain‐extension reaction in carbohydrate chemistry.
Zur‐Reaktionsweise von Enaminen mit Cyclopropenonen III. Isolierung eines Produktes der «C, C‐Insertion»
Authors: Bilinski V. , Dreiding A. S. 
Published: December 2004

AbstractFrom the reaction of the N‐(2‐Methylpropenyl)‐pyrrolidin 6 with diphenylcyclopropenone 7 we isolated as a byproduct 5‐Methyl‐2, 4‐diphenyl‐1‐pyrrolidino‐hexa‐1, 4‐diene‐3‐one 9. The structure was proven by an interpretation of the IR.‐, NMR.‐ and MS.‐spectra. This result is of importance since it represents the first case of a direct ‘C, C‐insertion’ product 4 from the reaction of an enamine 1 and a cyclopropenone 2 and because structures of type 4 (including 9) have previously been postulated for the main products of this reaction, which were later shown to be amides 3 (including 8).Acid hydrolysis of the β‐amino‐dienone 9 yielded the dihydropyrone 10 and the cyclopentenone 11. These isomeric products are considered to be the result of two electrocyclic reactions, one of a hexa‐2,4‐diene‐al 12 and the other of a hexadienylium ion 14.
Thermodynamique des mélanges liquides binaires. Volume de mélange d'alcanes normaux et ramifies
Authors: Steiger M. , Boissonnas Ch. G. , Fernández‐García J. G. , Stoeckli H. F. 
Published: December 2004

AbstractVolumes of mixing were determined by dilatometric measurements between 15° and 50°C for isomeric alkanes with n‐hexadecane and n‐dodecane. The negative excess volumes vary linearly with temperature.
Composés d'addition des halogénures de niobium(V) et de tantale(V): VI. Réactions d'échange des composés du chlorure de niobium(V) avec quelques nitriles
Authors: Merbach A. , Bünzli J. C. 
Published: December 2004

AbstractThe ligand exchange reactions NbCl5·ŘN + RCN* ⇄ NbCl5 · RCN* + RCN are studied by NMR. spectroscopy for R = Me3C, Me, FCH2, CICH2, BrCH2, ICH2. The reaction is of zero order in RCN and of first order in NbCl5 · RCN and thus a dissociative mechanism is suggested for all the ligands studied. The enthalpies and entropies of activation are determined over 50° to 90° temperature ranges. There is a linear correlation between ΔG≠ and the free enthalpy of formation of NbCl5 RCN. However this correlation is shown to hold only for series of adducts having the same donor group.
Über das Aroma der gelben Passionsfrucht. (Passiflora edulis f. flavicarpa). Vorläufige Mitteilung
Authors: Winter M. , Klöti R. 
Published: December 2004

AbstractA concentrate of the volatile flavor of yellow passion fruit (Passiflora edulis f. flavicarpa) has been prepared. Investigation by gas liquid chromatography and mass spectrometry led to the identification of 165 compounds, 161 of which were not previously found in passion fruit. Some of these substances are new naturally occurring flavor compounds.
Steroidal Heterocycles 15. 4,4‐Dialkyl‐Δ5‐3‐oxosteroids, 1,4′‐spiro [cycloalkyl‐Δ5hyphen;3‐oxo‐steroids] and Derivatives
Authors: Neumann H. C. , Stonner F. W. 
Published: December 2004

AbstractHomologs of 17‐hydroxy‐4,4‐17α‐trimethyl‐3‐oxo‐androst‐5‐ene‐2α‐carbonitrile (6d), such as the 4,4‐diethyl‐(6a), 4,4‐cyclopentyl‐(6c) and 4,4‐cyclohexyl‐(6b) analogs were synthesized.
Einlagerung hochenergetischer Tritiumatome in cis‐Cycloocten
Authors: Jordan P. , Reichen W. 
Published: December 2004

AbstractThe substitution, in liquid cis‐cyclooctene, of thermal tritiumatoms and reoil tritiumatoms from the nuclear reaction 6Li(n, α)3H was studied, and compared to earlier results obtained with cyclohexene. An explanation for the observed very distinct differences is proposed.
Stoffwechselprodukte von Mikroorganismen. 107. Mitteilung [1]. Die Struktur des Chlorothricins, eines neuartigen Makrolid‐Antibioticums
Authors: Muntwyler R. , Keller‐Schierlein W. 
Published: December 2004

AbstractChemical and spectroscopic evidence for the structural formula 9 of chlorothricolide methyl ester, derived from the aglycone of the antibiotic chlorothricin, is given. By chemical degradation and spectroscopic investigations structure 41 is deduced for the intact antibiotic.
α‐Chlor‐nitrone I: Darstellung und Ag+‐induzierte Reaktion mit Olefinen. Über synthetische Methoden, 5. (vorläufige) Mitteilung
Authors: Kempe U. M. , Das Gupta T. K. , Blatt K. , Gygax P. , Felix Dorothee , Eschenmoser A. 
Published: December 2004

AbstractOrganic synthesis may be said to be in need of enophiles, i.e. reagents that would undergo cycloaddition reactions with any isolated olefinic double bond, in contrast to most of the classical Diels‐Alder or 1,3‐dipolar addition reagents which, as a rule, require activated olefins in order to participate smoothly in cycloaddition processes. This paper introduces α‐chloronitrones as precursors of a new class of such reagents; they undergo an Ag+‐induced reaction with unactivated olefins with great ease to give products considered to result from 1,4‐cycloadditions of N‐alkyl‐N‐vinyl‐nitrosonium ions to the carbon‐carbon double bond (see scheme 2). This process is believed to have a number of synthetic applications, two of them being illustrated in two subsequent communications.
Premières études sur la biogénèse de la proferrorosamine A
Authors: Pouteau‐Thouvenot M. , Padikkala J. , Barbier M. , Helbling A. , Viscontini M. 
Published: December 2004

AbstractNous avons pu montrer à l'aide de substances radioactives que l'acide picolique est le précurseur immédiat de la proferrorosamine A. L'acide glutamique peut être transformé par Pseudomonas roseus fluorescens en acide picolique puis être incorporé dans la partie pyridinique du propigment tandis que les atomcs de carbone formant le noyau pyrrolinique provienncnt d'autrcs métabolites que nous n'avons pas encore identifiés. La lysine semble jouer le même rêle que I'acide glutaminique et ceci d'une manière encore plus prononéc.
The Reaction of Norbornene with Lead Tetraacetate and Thallium Trinitrate. Preliminary communication
Authors: Kagan Jacques 
Published: December 2004

AbstractThe reaction of norbornene with lead tetraacetate is found to be much more complex than previously reported. In acetic acid and in benzene, the syn‐7‐norbornenyl, 3‐nortricyclyl, and syn and anti‐7‐acetoxy‐exo‐2‐norbornyl acetates were characterized. In methanol, the isolated products represented most of those expected from the competition of methanol and acetate in the neutralization of the intermediate carbocations. The reaction of norbornene with thallium trinitrate in the above solvents yielded very complex mixtures besides the above mentioned products which were formed in about 50% yield.
The Effect of Solvent Variation on Nucleophilic Substitution Rates of Methyl Tosylate
Authors: Müller Paul , Siegfried Bernard 
Published: December 2004

AbstractRates of the reactions between bromide ion and methyl tosylate have been determined in 12 solvents and extrapolated to infinite dilution. The data are correlated with Parker's solvent activity coefficients by means of an empirical equation of the type: logks – logk0 = A log0γ + B with the constants A = 0.788 and B = 0,108 and a correlation coefficient of 0.983.
Die Wechselwirkung zwischen Walsh‐ und π‐Orbitalen im 7‐Cyclopropyliden‐norbornadien
Authors: Brogli F. , Heilbronner E. , Ipaktschi J. 
Published: December 2004

AbstractThe qualitative analysis of the PE.‐spectrum of 7‐cyclopropylidene‐norbornadiene (3) shows that the ‘through‐space’ interaction of the eA‐Walsh orbital with the antisymmetric linear combination \documentclass{article}\pagestyle{empty}\begin{document}$ {{\pi _ - = (\pi _a - \pi _b)} \mathord{\left/ {\vphantom {{\pi _ - = (\pi _a - \pi _b)} {\sqrt 2}}} \right. \kern-\nulldelimiterspace} {\sqrt 2}} $\end{document} of the two π‐orbitals in 3 is of the same order as the analogous interaction between π‐ and the π‐orbital of the exocyclic double bond in 7‐isopropylidene‐norbornadiene (2).
Isolierung, Molekulargewichtsbestimmung und alkalischer Abbau von Drosopterin und Isodrosopterin ‐ Augenpigmente der Fruchtfliege Drosophila melanogaster. Pteridine, LII
Authors: Schlobach Heinrich , Pfleiderer Wolfgang 
Published: December 2004

AbstractThe isolation of the eye pigments drosopterin and isodrosopterin from Drosophila melanogaster, their molecular weight determination and the alkaline degradation of the pigments is described. The identification of 6 hydrolysis products leads to the proposal of a new structural formula for the drosopterins as atropisomeric dipterinyl‐methane dyestuffs (13).
Synthese und Reaktionen von Droso‐ und Isodrosopterin. Pteridine, LIV
Authors: Schlobach Heinrich , Pfleiderer Wolfgang 
Published: December 2004

AbstractThe synthesis of the Drosophila pigments droso‐ and isodrosopterin (7) from 7.8‐dihydropterin (3) and 2‐hydroxy‐3‐oxobutyric acid (4) is described. A reaction mechanism is discussed and proven by isotope experiments. Droso‐ and isodrosopterin form in weak acidic medium in the presence of NH ions two red reaction products each one of which seems to be identical with neodrosopterin.
The Ring Expansion ‐ Ring Contraction Dichotomy in Aromatic Nitrene and Carbene Reactions II. Hetarylnitrenes. Preliminary communication
Authors: Wentrup C. , Thétaz C. , Gleiter R. 
Published: December 2004

Abstract15N‐labelling experiments and energy calculations on nitreno‐azines and ‐diazies are in agreement and lead to the theory that both ring contraction and ring expansion in hetarylnitrenes can be one‐step processes which are governed mainly by the energy differences between the reacting species and the products.
Eine einfache Darstellungsmethode für Nucleosid‐5′amidophosphorsäurediester
Authors: Kvita Vratislav , Baschang Gerhard 
Published: December 2004

AbstractThe reaction of phosphites with derivatives of 5′‐azido‐uridine and 5′‐azidoadenosine in the presence of nucleophiles is a simple method to obtain the corresponding 5′‐amidophosphoric esters. The dependency of heterocyclic alkylation of reaction temperature and solver has been investigated.
Säurekatalysierte Dienon‐Phenol‐Umlagerungen von Allylcyclohexadienonen; ladungsinduzierte und ladungskontrollierte sigmatropische Reaktionen
Authors: Widmer U. , Zsindely J. , Hansen Hans‐Jürgen , Schmid Hans 
Published: December 2004

AbstractThe rearrangement of 10‐allyl‐2‐oxo‐Δ1(9), 3‐hexahydronaphthalene (12) catalysed by trifluoroacetic acid and other Bronsted acids yielded almost exclusively the [3s, 3s]‐products, 1‐ and 3‐allyl‐5,6,7,8‐tetrahydro‐2‐naphthol (16 and 15, respectively). The rearrangement of 12 with trifluoroacetic anhydride or acetic anhydride/sulfuric acid, yields, besides 15 and 16, appreciable amounts of the [1s, 2s]‐rearrangement product, 4‐allyl‐5,6,7,8‐tetrahydro‐2‐naphthol (14) (table 1).The CF3COOH catalysed dienone‐phenol‐rearrangement of 6‐ally‐5,6‐dimethyl‐cyclohexa‐2,4‐dien‐l‐one (11) in hexane at 0° yields4‐allyl‐2,3‐dimethyl‐phenol (19). Rearrangement of d3‐ll containing a specifically deuteriated allyl group proves that the formation of d3‐19 occurs via a [3s, 3s]‐sigmatropic reaction. On the other hand, treatment of 11 with (CF3CO)2O at 0° in hexane gives (after saponification) 4‐allyl‐, 5‐allyl‐ and 6‐allyl‐2,3‐dimethyl‐phenol (19, 20 and 21, respectivcly). This reaction occurs via an acyloxybenzenium‐ion intermediate. The reactions performed with d3‐11 demonstrate that the formation of d3‐19 occurs both by a direct [3s, 3s]‐shift and by a twofold [1s, 2s]‐shift, respectively. d3‐20 is formcd by a [3s, 4s]‐sigmatropic reaction. d3‐21 is obtained with about 95% inversion of the carbon skeleton of the allyl group. Thus d3‐21 is mainly formed by a [1s, 2s]‐ followed by a [3s, 4s]‐sigmatropic rearrangement.6‐Allyl‐6‐niethyl‐cyclohexa‐2,4‐dien‐1‐one (4) yields with CF3COOH in hexane 4‐allyl‐2‐methyl‐phenol (5), whereas with (CF3CO)2O in hexane 5, 3‐allyl‐ and 5‐allyl‐2‐methyl‐phenol (24 and 25, respectively) are formed in comparable amounts. As a minor product 6‐allyl‐2‐methyl‐phenol (26) was observed.Based on these observations, the concept of charge‐induced, e.g. schemes 2 and 3, and charge‐controlled, e.g. scheme 7, sigmatropic reactions, has been elaborated. In the former, the charge serves only to accelerate appreciably thermal orbital‐symmetry allowed reactions, whereas in the latter, the charge determines the course of the transformations according to the Woodward‐Hoffmann rules.Especially in acetylating systems, allylcyclohexdienones undergo charge‐induced and charge‐controlled reactions simultaneously.