bluuebunny/crossref_metadata_2025_split huggingface dataset:
Durch Bromierung ausgelöste Umlagerung tertiärer Allylalkohole: Der Einfluss eines Fluor‐Substituenten auf Reaktionsgeschwindigkeit und Reaktionsverlauf
Authors: Nagakura Isao , Savary Dang Ngoc‐Huê , Schlosser Manfred 
Published: December 2004

Rearrangement of Tertiary Allyl Alcohols Induced by Bromination: The Effect of a Fluorine Substituent on the Rate and the Outcome of the ReactionThe allyl alcohol bearing a methyl and a t‐butyl group at the hydroxylated position was found to undergo a rearrangement when treated with bromine (or N‐bromosuccinimide) in an aqueous medium and to afford a product mixture containing two regioisomeric ketones and one oxirane. Introduction of an additional methyl group or a fluorine atom at the non‐terminal olefinic center led to a more selective discrimination between potential migratory groups. As the result of an exclusive t‐butyl shift only one product, a ketone, was formed in both cases. Whereas the reaction rate was only slightly affected by the additional methyl group, it was substantially decreased by the fluorine atom.
Photochemistry of α, β‐Unsaturated γ, δ‐Epoxyesters I: Singlet versus Triplet Reactivity
Authors: Alder Alex Peter , Wolf Hans Richard , Jeger Oskar 
Published: December 2004

AbstractOn triplet excitation (E)‐2 isomerizes to (Z)‐2 and reacts by cleavage of the C(γ), O‐bond to isomeric δ‐ketoester compounds (3 and 4) and 2,5‐dihydrofuran compounds (5 and 19, s. Scheme 1). ‐ On singulet excitation (E)‐2 gives mainly isomers formed by cleavage of the C(γ), C(δ)‐bond (6–14, s. Scheme 1). However, the products 3–5 of the triplet induced cleavage of the C(γ), O‐bond are obtained in small amounts, too. The conversion of (E)‐2 to an intermediate ketonium‐ylide b (s. Scheme 5) is proven by the isolation of its cyclization product 13 and of the acetals 16 and 17, the products of solvent addition to b. ‐ Excitation (λ = 254 nm) of the enol ether (E/Z)‐6 yields the isomeric α, β‐unsaturated ε‐ketoesters (E/Z)‐8 and 9, which undergo photodeconjugation to give the isomeric γ, δ‐unsaturated ε‐ketoesters (E/Z)‐10. ‐ On treatment with BF3O(C2H5)2 (E)‐2 isomerizes by cleavage of the C(δ), O‐bond to the γ‐ketoester (E)‐20 (s. Scheme 2). Conversion of (Z)‐2 with FeCl3 gives the isomeric furan compound 21 exclusively.
Zur Photocyclisierung von N‐Phenacylformamiden
Authors: Wehrli Hansuli 
Published: December 2004

UV. Irradiation of N‐PhenacylformamidesUV. irradiation of suitable N‐phenacylformamides (e.g. 2) leads under transfer of the formyl H‐atom to the corresponding β‐lactams (e.g. 3). Scope and structural limitations of the novel reaction are discussed.
High Asymmetric Induction in Lewis Acid‐Promoted Intramolecular Ene‐Type Reactions: A diastereo‐ and enantioselective synthesis of (+)‐α‐allokainic acid. Preliminary Communication
Authors: Oppolzer Wolfgang , Robbiani Christian , Bättig Kurt 
Published: December 2004

AbstractThe monocyclic amino diacid (+)‐α‐allokainic acid 1 has been prepared enantioselectively from the ester of cis‐β‐chloroacrylic acid and (−)‐8‐phenylmenthol by a series of four synthetic operations in over 15% yield. The crucial step is the intramolecular ‘ene‐type’ reaction of the (Z)‐diene 4 which on treatment with a mild Lewis acid undergoes a highly accelerated, dia‐ and enantiostereoselective cyclization to give the pyrrolidines 6 and 7 in a ratio of 95:5 (Scheme 3). Subsequent ester hydrolysis regenerates the auxiliary chiral alcohol. Similar cyclization of the (E)‐diene 5 furnished a 15:85 mixture of 6 and 7 showing an efficient reversal of the optical induction by variation of the enoate geometry.
Stoffwechselprodukte von Mikroorganismen 205. Mitteilung.. Isolierung und Struktur von Streptazolin
Authors: Drautz Hannelore , Zähner Hans , Kupfer Ernst , Keller‐Schierlein Walter 
Published: December 2004

AbstractStreptazolin, a lipophilic neutral compound giving a yellow colour reaction with Ehrlich reagent, was isolated from cultures of Streptomyces viridochromogenes, strain Tü‐1678. On the basis of a “chemical screening”. Its structure, 1, was determined by spectroscopic investigations and chemical degradations. Dihydrostreptazolin 3 exhibits limited antimicrobial activities. Pharmacological investigations are in progress.
Synthesis, Characterization, and Biological Properties of Five Enkephalin‐like Pentapeptides Containingp‐Nitrophenylalanine
Authors: Fauchère Jean‐Luc , Schiller Peter W. 
Published: December 2004

AbstractFive pentapeptides with the amino acid sequenceL‐tyrosyl‐D‐alanyl‐glycyl‐L‐p‐nitrophenylalanyl‐X, wherein X =L‐leucine,L‐leucine amide,L‐methionine amide,L‐1‐adamantylalanine amide, andL‐neopentylglycine amide were prepared by chemical synthesis in solution and characterized chemically and physically. The effect of the incorporation of the unnatural amino acids adamantylalanine and neopentylglycine, ‘fat’‐analogues of leucine and methionine, on the inhibition of electrically evoked contractions of the myenteric plexus‐longitudinal muscle preparation from guinea pig ileum was studied. Their activities relative to the peptides with X = Leu · OH, Leu‐NH2, and Met‐NH2(X = Neo‐NH2is particularly potent) are discussed in terms of hydrophobic and steric factors, and resistance towards enzymic degradation.
Photochemical Reactions. 125th communication [1]. Photochemistry of homoconjugated cyclobutanones. I. Synthesis and photolysis of a Spiro [3.6]deca‐5, 7‐dien‐1‐one
Authors: Lyle Terry A. , Frei Bruno 
Published: December 2004

AbstractThe title compound 4 was prepared in 54% overall yield from eucarvone (5). On triplet sensitization 4 gives two products resulting from a 1,2‐acyl shift (8 and 9), whereas singlet excitation of 4 causes decarbonylation and ketene elimination (4 → 10 and 11).
Enantioselective Generation and Diastereoselective Reactions of Chiral Enolates Derived from α‐Heterosubstituted Carboxylic Acids. Preliminary Communication
Authors: Seebach Dieter , Naef Reto 
Published: December 2004

AbstractDioxolanones7and8aand oxazolinones9aderived from pivalaldehyde and lactic acid, mandelic acid, and proline, respectively, furnish chiral enolates of type3by deprotonation with LDA. Reactions of these enolates with alkyl halides, aldehydes, and ketones(→ 8b, 9b, 11–13)are highly diastereoselective. Thus, the overall enantioselective α‐alkylation of chiral, non‐racemic α‐heterosubstituted carboxylic acids(4 → 6)is realized.
Substitution of HMPT by the cyclic urea DMPU as a cosolvent for highly reactive nucleophiles and bases
Authors: Mukhopadhyay Triptikumar , Seebach Dieter 
Published: December 2004

AbstractThe cyclic urea DMPU (N, N′‐dimethyl‐N, N′‐propylene urea = 1,3‐dimethyl‐2‐oxo‐hexahydropyrimidine) is shown to exhibit the same effects HMPT in oxirane‐opening with Li‐acetylide, in a Wittig olefination, in the double deprotonation of nitroalkane, in the Michael addition of Li‐dithiane to cyclohexenone, and in selective generations of certain enolates (Schemes 1–7) DMPU might therefore be as safe substitute of the carcinogenic HMPT as a cosolvent with unique properties in diverse type of reaction.
Metal complexes with macrocyclic ligands. XVI. Spectrophotometric and thermodynamic studies of solvents and unidentate ligands interaction with the pentacoordinate Co2+‐, Ni2+‐ and Cu2+‐complexes of 1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane
Authors: Micheloni Mauro , Paoletti Piero , Bürki Stephan , Kaden Thomas A. 
Published: December 2004

AbstractThe interaction of solvents and of unidentate ligands such as N, SCN−, OCN− and OH− with the Co2+‐, Ni2+ and Cu2+‐complexes of 1,4,8,11‐tetramethyl‐1,4,8,11‐tetraazacyclotetradecane (TMC) have been studied by Spectrophotometric and calorimetric techniques. The spectra in different solvents (Table 2) show that the Ni2+‐ and probably also the Cu2+‐complex with TMC exist as square planar or pentacoordinate species or as a mixture of both, depending on the donor properties of the solvent. The [Co(TMC)]2+‐complex is pentacoordinate in all the solvents studied.Ternary complexes [M(TMC)X]n+ are also formed by the unidentate ligands X = N, OCN−, OH−, F− and NH3 and their stability constants have been determined. Interesting is the high selectivity of [Ni(TMC)]2+ towards the addition of a further donor (Table 3). Only small ligands such as those listed above form stable adducts, whereas the larger ones such as imidazole or pyridine do not. This is a consequence of the special structure of the complex and of the trans‐I‐(RSRS)‐ conformation of the ligand in these complexes. Since the four methyl groups are all on the side of the macrocycle to which the additional unidentate ligand binds, steric interaction between the four methyl groups and the larger ligands prevents the formation of the adducts.The calorimetric measurements show that the stability of the complexes [M(TMC)X]n+ is due to both an enthalpic and entropic contribution which differ in their magnitude (Table 4). This indicates that several antagonistic factors are important in determining the overall stability.
Copper(I)‐ and Copper(II)‐catalyzed Diels‐Alder Additions of α‐Substituted Acrylonitrile to Furan. The Synthesis of 7‐Oxa‐bicyclo[2.2.1]hept‐5‐en‐2‐one
Authors: Vieira Eric , Vogel Pierre 
Published: December 2004

AbstractThe difficult Diels‐Alder additions of α‐acetoxy‐ and α‐chloroacrylonitrile to furan can be run at 20–35° and atmospheric pressure in the presence of CuCl. Cu(BF4) · 6 H2O, Cu(OOCCH3)2 · H2O or cupric tartrate · 3H2O. Under kinetic control, the exo‐carbonitrile adducts 2 and 8, respectively, are favoured. Saponification of the 2endo‐acetoxy‐7‐oxabicyclo[2.2.1]hept‐5‐ene‐2exo‐carbonitrile (2) furnished the 7‐oxabicyclo[2.2.1]hept‐5‐en‐2‐one (4). Basic hydrolysis of the adducts (8 + 9) of α‐chloroacrylonitrile to furan and its 5exo, 6exo‐isopropylidenedioxy derivatives did not give the corresponding ketones, the carboxamides 14 + 15 and 16 + 17, respectively, were isolated.
13C‐NMR.‐Spektren von 3H‐Benz[cd]azulen‐3‐onen
Authors: Neidlein Richard , Kramer Walter , Schcutzow Dieter 
Published: December 2004

13C‐NMR. Spectra of 3H‐benz[cd]azulenc‐3‐ones13C‐NMR. Spectra of 7,9‐dimethyl‐3H‐benz[cd]azulenc‐3‐one (2) and 7,9‐dimethyl‐4,5‐dihydro‐3H‐benz[cd]azulene‐3‐one (7) in CDCl3 and CF3CO2D are reported. The assignment of signals was achieved with the aid of selective proton decoupling, non‐decoupled spectra and comparison with spectra of simple azulene‐derivatives. The major localization of positive charge in the cationic 3‐hydroxybenz‐[cd]azulenium system was found in the six‐ and seven‐membered ring, which suggests in accordance with calculated π‐electron densities the structure of a benztropylium ion rather than a bridged azulenium ion.
The Low‐Temperature UV./VIS. Absorption Spectrum of [18]Annulene
Authors: Baumann Harold , Oth Jean F. M. 
Published: December 2004

AbstractThe UV./VIS. absorption spectrum of [18]annulene has been remeasured in 3‐rnethylpentane at room and at liquid nitrogen (glass) temperature and interpreted by the CNDO/S‐CI‐method. The confrontation of the experimental electronic transitions with the CNDO/S‐CI‐calculated ones favors a structure with D6h‐symmetry, i.e, a structure with delocalized π‐bonds.
The Photooxygenation of Heptamethyl Coα, Coβ‐Dicyanocobyrinate
Authors: Kräutler Bernhard 
Published: December 2004

AbstractIrradiation with visible light of an oxygen‐saturated methanolic solution of heptamethyl Coα, Coβ‐dicyanocobyrinate and of the sensitizer methylene blue causes the efficient photooxygenation of this vitamin B12 derivative. Use of CD3OD instead of CH3OH strongly accelerates the reaction. This solvent H/D‐isotope effect is consistent with a mechanism involving ‘singlet oxygen’ and is exploited preparatively. Two photooxygenation products can be isolated from such preparative experiments. One of these, isolated in 47% yield, has NMR.‐spectral characteristics identical with those of Inhoffen's heptamethyl Coα,Coβ‐dicyano‐5,6‐dioxo‐5,6‐secocobyrinate (2a). To the other photoproduct, isolated in 25% yield, the structure of the unknown isomeric heptamethyl Coα, Coβ‐dicyano‐14,15‐dioxo‐14, 15‐secocobyrinate (3a) is assigned.
Synthese von Glycerylätherphosphatiden 2. Mitteilung Herstellung von 2‐O‐Acetyl‐1‐O‐[(Z)‐9‐octadecenyl] ‐sn‐glyceryl‐3‐phosphorylcholin («Oleyl‐PAF»), des Enantiomeren sowie einiger analoger, ungesättigter Verbindungen
Authors: Hirth Georges , Saroka Hervé , Bannwarth Wilhelm , Barner Richard 
Published: December 2004

Synthesis of Glyceryletherphosphatides, 2nd Communication. Preparation of 2‐O‐Acetyl‐1‐O‐[(Z)‐9‐octadecenyl]‐sn ‐glyceryl‐3‐phosphorylcholin (‘Oleyl‐PAF’), of its Enantiomer and Some Analogous, Unsaturated CompoundsSyntheses of the unsaturated glyceroletherphospholipid 1a as an olefin‐analog of ‘Platelet Activating Factor’ (PAF) are described together with the methods for the preparation of the enantiomer 1′a, the corresponding ‘lyso compounds’ 1b and 1′b and their positional isomers 21a, 21′a, 26, 26′, 25, 25′ obtained on formally exchanging the attachment site of the functional groups at the glycerol moiety. Structural assignments and optical purity of the compounds are confirmed.
Metal complexes with macrocyclic ligands. Part XIX. Synthesis and Cu2+‐complexes of a series of 12‐, 14‐ and 16‐membered cis‐ and trans‐N2S2‐macrocycles
Authors: Siegfried Liselotte , Kaden Thomas A. 
Published: December 2004

AbstractA series of 12‐, 14‐, and 16‐membered N2S2‐macrocycles (9–11 and 19–21) with cis and trans‐arrangement of the heteroatoms have been synthesized by high‐dilution cyclization and subsequent reduction of the amides with B2H6. With these ligands the corresponding Cu2+‐complexes were prepared and their UV/VIS spectra, their electrochemistry and their EPR properties have been studied. Generally three absorption bands at 270–320 nm, 330–370 nm and 530–620 nm can be observed in aqueous solution and these have been assigned to the N→Cu2+ and S→Cu2+ charge‐transfer bands and to the d‐d* transition, respectively. The cyclic voltammetry in CH3CN shows in all cases a reversible or quasi‐reversible Cu2+/Cu+‐transition at potentials of 10–480 mV against SHE. The values of g‖ and A‖ obtained from EPR spectra indicate that the geometry of the Cu2+‐complex of the 14‐membered cis‐N2S2‐macrocycle is less distorted than that of the other complexes.
The Halide‐promoted fragmentation of 1‐chloro‐1‐fluoro‐2‐(a‐silylakyl))cyclopropanes: A new entry to fluorodienes
Authors: Schlosser Manfred , Dahan Rahel , Cottens Sylvain 
Published: December 2004

AbstractWhen heated in the presence of tetrabutylammonium fluoride or chloride, 1‐chloro‐1‐fluoro‐2‐(trimethylsilyl)methyl‐cyclopropanes (1, 2 and 3) undergo smooth ring‐opening fragmentation to afford 2‐fluoro‐butadienes ((4, 5 and 6 resp.) with high yields. Despite unfavorable geometries, the reaction is concerted and the inversion mode of rotation dominates over the retention mode by a factor roughly 100.
Preparation and Properties of Bis[μ‐S‐(2‐tiolatoethyl)‐diphenylphosphine][(2‐thiolatoethyl)diphenyl‐phosphine]dinickel(+1) Ion, a Novel Unsymmetrical Thiolate‐bridged complex
Authors: Pfeiffer Ernst , Pasquier Maurice L. , Marty Werner 
Published: December 2004

AbstractThe title cation ( = Ni2L) is formed in a variety of reactions (Schemes 1 and 2) in systems containing Ni2+ and (2‐thiolatoethyl)‐diphenylphosphine (= L−) in the absence of coordinating anions at Ni2+/L− ratios > 0.5 in apolar or moderately polar media. Solid [Ni2L3]CIO4 and [Ni2L3]BPh4 have been isolated. Job's plots confirm the Ni2L‐ stoichiometry in solution. 31P‐NMR data are consistent with ≥ 97% Ni2L (vs. ⩽ 3% of hypothetical Ni3L) at equilibrium and support the suggested configuration (Fig. 2). The equilibrium between NiL2 + NiL2Br2 and Ni2L + Br− varies with the solvent composition in CH23Cl2/EtOH mixtures. The rate of formation of Ni2L2Br2 from Ni2L and bromide (in high excess) in CH2Cl2 is first‐order in [Ni2L]tot but depends on the ratio [Bu4NBr]tot/[Ni2L3 · ClO4]tot, even at a high excess of bromide. This is interpreted by efficient competition in ion‐aggregate formation between the small perchlorate concentration introduced as the counterion of Ni2L, and the large excess of bromide.
Zum Mechanismus der Aziridinsynthese aus 2‐Azidoalkoholen und Triphenylphosphin
Authors: Pöchlauer Peter , Müller Ernst Peter , Peringer Paul 
Published: December 2004

On the Mechanism of the Aziridine Synthesis from 2‐Azido‐alcohols and TriphenylphosphineThe reaction of selected 2‐azido‐alcohols, their pivalates, and methanesulfonates with triphenylphosphine was investigated. It is shown that the formation of aziridines from 2‐azido‐alcohols proceeds via 1,3,2λ5oxazaphospholidines. Furthermore, the first synthesis of the unsubstituted acenaphtene‐1,2‐imine is described.
Preparation by yeast reduction and determination of the sense of chirality of enantiomerically pure ethyl (−)‐4,4,4‐trichloro‐3‐hydroxy‐ and (+)‐4,4,4‐trifluoro‐3‐hydroxybutanoate
Authors: Seebach Dieter , Renaud Philippe , Schweizer W. Bernd , Züger Max F. , Brienne Marie‐Josèphe 
Published: December 2004

AbstractReduction of ethyl 4,4,4‐trichloro‐ and 4,4,4‐trifluoro‐3‐oxobutanoate by fermenting baker's yeast (Saccharomyces cerevisiae) on a preparative scale (20–50 g in ca. 3 1 of H2O) gave 70–80% yields of the trichloro‐ [(−)‐(S)‐1a] and trifluoro‐hydroxyesters [(+)‐(R)2a] of ca. 85 and 45% ee, respectively. Both, (−)‐1a and (+)‐2a could be obtained in > 98% ee by subsequent crystallization (of(−)‐1, (+)‐2a or the 3,5‐dinitrobenzoate (+)‐2b. The absolute configuration of both hydroxyesters was determined (a) by chemical correlation ((−)‐1a), (b) from the melting diagrams and mixed melting points (differential‐scanning calorimetry Fig. 1) of the dinitrobenzoates of the CF3‐derivative (+)‐2a and its CH3‐analogue 8, and c) by X‐ray analysis of the ester 2f from (+)‐2a and (−)‐camphanoyl chloride (Fig. 2 and 3).
Addition von Dimethylketen an 6‐heterosubstituierte Fulvene. Synthese von (±)‐Filifolon
Authors: Stadler Heinz , Rey Max , Dreiding André S. 
Published: December 2004

Addition of Dimethylketene to 6‐Heterosubstituted Fulvenes. Synthesis of (±)‐Filifolone[2 + 2]Cycloaddition of dimethylketene to 6‐ethoxy‐ (8) and 6,6‐(tetramethylenedithio)fulvene (9) gave the 4‐alkylidenebicyclo[3.2.0]heptenones 11 and 12, respectively. Under the same conditions, 6‐(dimethylamino)fulvene (7) was acylated to yield the push‐pull fulvene 10. Raney‐Ni reduction converted the adduct 12 into the monoterpene (±)‐filifolone ((±)‐1, 52%) and minor amounts of the four related ketones 14‐17. Cycloaddition of a second dimethylketene to the primary cycloadduct 11a yielded the cis, transoid, cis‐tricyclic diketone 13.
Synthesis of aristoteline‐type alkaloids. Part II. The structure of neohobartine, a side product of the hobartine‐aristoteline transformation
Authors: Borschberg Hans‐Jürg 
Published: December 2004

AbstractThe structure of neohobartine (3), a side product of the acid‐catalyzed conversion of (−)‐hobartine (1) into (+)‐aristoteline (2), has been elucidated by spectroscopic methods. Possible mechanistic pathways leading to its 1‐azaaadamantane skeleton are discussed.
Reversed Stereochemical Course of the Michael Addition of Cyclohexanone to β‐Nitrostyrenes by Using 1‐(Trimethylsiloxy)cyclohexene/Dichloro(diisopropoxy)titanium. Preliminary Communication
Authors: Seebach Dieter , Brook Michael A. 
Published: December 2004

AbstractInduced by a stoichiometric excess of dichloro(diisopropoxy)titanium, 1‐(trimethylsiloxy)cyclohexene and p‐substituted β‐nitrostyrenes (Y = H,CH3,CH3O,CN) combine in CH2Cl2 solution at −90° preferentially with relative topicity ul – opposite to the corresponding reaction of enolates or enamines. The primary products are the bicyclic nitronates 3–5 which can be separated, and which are cleaved by KF in MeOH to give the aryl(nitroethyl)‐substituted cyclohexanones 1 and 2 (Tables 1 and 2, two typical procedures are given). The major products (2:1 to 4:1) are the hitherto not readily available diastereoisomers 2 of l‐configuration. Instead of being solvolyzed, the bicyclic nitronate 5 can be used for nitroaldol additions (→6) and for [3 + 2]‐dipolar cycloadditions (→7), diastereoselectively furnishing products with 4 asymmetric C‐atoms (not counting acetal centers). The Michael addition described here is yet another example of an ul‐combination of trigonal centers induced by Lewis acids, overriding the influence of the configuration of the donor component.
Gas‐Phase Basicities of Open‐Chain and Cyclic Diols from Dissociations of Ammonium Adducts, Protonated Mixed Dimers and ICR Experiments. Structural and Stereochemical Effects
Authors: Guenat Christian , Houriet Raymond , Stahl Daniel , Winkler Johann 
Published: December 2004

AbstractThe gas‐phase basicity (GB) of open‐chain and cyclic diols and triols has been determined by the method of dissociation of proton‐bound adducts using 1,4‐butanediol and cis‐ and trans‐1,3‐cyclohexanediol as reference compounds. The GB and proton affinity (PA) of the two cyclic reference diols have been obtained in ion‐cyclotron‐resonance experiments. The unimolecular and the collision‐activated dissociations of the ammonium adducts of the polyols allow a ranking of their GB and PA values which reflects the various structural and stereochemical effects. The possibility of internal H‐bonding between the two OH groups leads to a strong increase of the PA values. The incremental effect of chain length on the PA of open‐chain diols is evidenced, as well as the detailed influence of the configuration and conformation for cyclopentane‐ and cyclohexanediols, and ‐triols. These experiments also emphasized the predominant role of doubly H‐bound ammonium/diol chelate conformations as opposed to singly proton‐bound species.
Site Selectivity in the Gas‐Phase Ionic Phenylation of Alcohols and Alkyl Chlorides
Authors: Keheyan Yeghis , Speranza Maurizio 
Published: December 2004

AbstractFree, unsolvated phenylium ions formed by the spontaneous β decay of [1,4‐3H2]benzene have been allowed to react with gaseous alcohols (ROH: R = Et, CF3CH2, Pr, or i‐Pr; partial pressure: 3–56 Torr) and alkyl chlorides (R′Cl: R′ = Pr, i‐Pr, or Bu; partial pressure: 20–450 Torr), in the presence of a thermal radical scavenger (O2: 4 Torr). Phenylium ion confirms its considerable site selectivity, demonstrated by the distinct preference toward the n‐centre of the substrate (46–100%), although significant insertion into the alkyl group of alcohols is observed as well. Phenylium ion displays significant positional selectivity even between different n‐type sites in a bidentate molecule such as CF3CH2OH. An affinity F < O < Cl trend is observed, which indicates a direct relationship between the polarizability of the n‐centre of the molecule and its orienting properties toward phenylium ion. The stability features of the ionic intermediates from addition of phenylium ion with ROH or R′Cl have been evaluated, as well as their fragmentation and isomerization mechanisms. The behaviour of phenylium ion toward the selected substrates in the gas phase is discussed and compared with previous mechanistic hypotheses from related nuclear‐decay studies.