Stereochemistry of the Electrophilic Homoallylic Chlorination Reaction of Sterically Congested Alkenes with Benzenesulfenyl Chloride: The Structure of the Phenylthiiranium Ion Intermediate

Huang, Xicai; Batchelor, Raymond J.; Einstein, Frederick W. B.; Bennet, Andrew J.

doi:10.1021/jo00102a042

Cited by 33 publications

(28 citation statements)

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“…The C‐Te‐C bond angle is therefore larger (37.07°) than that in the tellurirenium ion (34.1°) . The experimentally determined bond lengths of the central C−C bonds of the [Ad 2 SeEt] + , [Ad 2 SePh] + and [Ad 2 TePh] + structures, including the those of Ad−Ad and Ad=Ad and those of the known [Ad 2 SEt] + [3d] and [Ad 2 SPh] + ions, show a linear correlation with the NBO calculated s character of these bonds (Figure ; for values, see Figure S2 in the Supporting Information).…”

Section: Resultsmentioning

confidence: 79%

Seleniranium and Telluriranium Salts

Poleschner

Seppelt

2018

Chemistry A European J

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Seleniranium salts [Ad SeR] X (2-8), which are moderately stable at room temperature, were synthesized by addition of RSe X equivalents to the bulky olefin bis(adamantylidene) Ad=Ad (1), where R is aryl or alkyl and X is Tf N , B(C F ) , or SbCl . Unstable telluriranium salts [Ad TeR] X (9-12) were obtained by addition of RTe X equivalents to 1 (R=Ph, Et; X =Tf N , BF ). The compounds were characterized by NMR spectroscopy and quantum chemical calculations, and the Se compounds also by ESI mass spectrometry. Crystal structures were determined for seleniranium salts 2 and 7 and telluriranium salt 9.

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Section: Resultsmentioning

confidence: 79%

Seleniranium and Telluriranium Salts

Poleschner

Seppelt

2018

Chemistry A European J

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“…[23][24][25] Structural studies support the plausibility of episulfonium ions (thiiranium ions), [26][27][28][29] thiirenium ions, [28,29] and related episelenonium ions. [30] For example, X-ray structures of episulfonium ions 11, [30] 12, [27] and 13 [28,29] have been reported (Figure 2). In addition, bromonium and iodonium ions have also been characterized by X-ray crystallography.…”

Section: Evidence For Episulfonium Ionsmentioning

confidence: 99%

Nucleophilic Substitution Reactions of 2‐Phenylthio‐Substituted Carbohydrate Acetals and Related Systems: Episulfonium Ions vs. Oxocarbenium Ions as Reactive Intermediates

2008

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A powerful approach for controlling the stereochemistry of glycosylation reactions involves using a directing group at an adjacent carbon to influence the stereochemistry of nucleophilic attack. The use of substituents such as I, PhS, and PhSe has proven to be especially valuable because it enables the preparation of 2‐deoxysugars after reductive removal of the directing group. The mechanisms of these reactions are generally considered to involve nucleophilic opening of bridged onium ions and to proceed with inversion. Onium ions, however, equilibrate with open cations, and these open forms can be favored when the cation is highly stabilized. Although the selectivities of reactions of carbohydrate‐derived cations are consistent with the intermediacy of onium ions, the reactions of acyclic cations are not. Instead, consideration of the preferred conformations of the oxocarbenium ions and stereoelectronically favored additions to these intermediates provides a predictive model to explain the diastereoselectivities observed in reactions of oxocarbenium ions bearing proximal heteroatoms.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

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“…[2a, 4] Interestingly, salts of 2,3-di-and 2,2,3,3-tetra-alkylthiiranium ions bearing both small and bulky substituents in the ring have been isolated at room temperature, for example 2, which is stable for several weeks at À 10 8C. [5,6] NMR spectroscopy [5] and X-ray diffraction [6,7] measurements have again provided unambiguous proof of the identities of such salts. Salts of thiiranium ions that are unsubstituted at carbon or with 2,3-di-or 2,2,3-trimethyl substitution have yet to be isolated, although the existence of the latter two compounds in cold sulfur dioxide has been confirmed by NMR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Are Pi-Ligand Exchange Reactions of Thiirenium and Thiiranium Ions Feasible? An Ab Initio Investigation

Sølling¹,

Wild²,

Radom³

1999

Chem. Eur. J.

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Ab initio calculations at the G2 level have been employed to investigate the hitherto unobserved p-ligand exchange reactions of thiirenium and thiiranium ions. Two pathways for exchange and one pathway for insertion are presented. The lower energy exchange pathway has barriers of 19.8 ± 46.6 kJ mol À1. The barriers for the second exchange pathway and for the insertion reaction are considerably larger. The calculations predict that p-ligand exchange is indeed feasible for thiirenium and thiiranium ions, that the exchange reaction is stereospecific with respect to the configuration at sulfur, and that insertion will not compete with exchange despite a high thermodynamic driving force for the former. These conclusions closely parallel those reached in a recent theoretical investigation of the corresponding phosphorus systems for which p-ligand exchange was observed experimentally.

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Stereochemistry of the Electrophilic Homoallylic Chlorination Reaction of Sterically Congested Alkenes with Benzenesulfenyl Chloride: The Structure of the Phenylthiiranium Ion Intermediate

Cited by 33 publications

References 0 publications

Seleniranium and Telluriranium Salts

Seleniranium and Telluriranium Salts

Nucleophilic Substitution Reactions of 2‐Phenylthio‐Substituted Carbohydrate Acetals and Related Systems: Episulfonium Ions vs. Oxocarbenium Ions as Reactive Intermediates

Are Pi-Ligand Exchange Reactions of Thiirenium and Thiiranium Ions Feasible? An Ab Initio Investigation

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