Carbon acids. 13. Acidifying effects of phenylthio substituents

Bordwell, F. G.; Bares, Joseph E.; Bartmess, John E.; Drucker, George E.; Gerhold, John; McCollum, Gregory J.; Puy, Michael Van Der; Vanier, Noel R.; Matthews, Walter S.

doi:10.1021/jo00422a033

Cited by 102 publications

(57 citation statements)

References 12 publications

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“…This may be explained by the lower acidity of the α-hydrogen atoms relative to those in the sulfur analogs. [40] The presence of the methylene spacers in sulfide 7a had a great effect on the rate of the reaction. Thus, the reaction of sulfide 4a was complete after 4 h, whereas the analogous reaction of 7a required 2 d (Table 1, Entry 12).…”

Section: Methodsmentioning

confidence: 99%

Base-Catalyzed Reactivity of Sulfur- and Selenium-Bridged Cyclic Alkynes: Tandem Isomerization and Cycloaromatization versus Isomerization and Nucleophilic Addition

et al. 2002

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Section: Methodsmentioning

confidence: 99%

Base-Catalyzed Reactivity of Sulfur- and Selenium-Bridged Cyclic Alkynes: Tandem Isomerization and Cycloaromatization versus Isomerization and Nucleophilic Addition

et al. 2002

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“…[7] and involves the intermediacy of a chloroalkyl phenylsulfonyl carbanion, -:CC 1RS02Ph. We reasoned that this cleavage reaction could perhaps be disfavoured by employing an alkylsulfonyl residue in place of the phenylsulfonyl moiety (29), and proceeded to explore the chemistry of the equivalent compounds leading to 7 and 15, but instead incorporating the P a reasontert-butylsulfonyl group. This was chosen to provid, able degree of steric hindrance around the sulfonyl group so as to afford adequate diastereoselectivity in the reduction of the appropriate P-ketosulfones (27).…”

Section: Phchomentioning

confidence: 99%

“…We reasoned that this cleavage process would be facilitated by the phenylsulfonyl group, which would strongly stabilize the carbanion -:CEtCISO2Ph, 23 (29), and that this stabilization would be decreased by the use of a sterically hindered tert-butylsulfonyl group. Hence, the two series of compounds, 16-21, were prepared.…”

mentioning

confidence: 99%

Stereochemical studies on the formation of α,β-epoxysulfones using α-chloro-β-hydroxysulfones of known configuration

Grossert¹,

Sotheeswaran²,

Dharmaratne³

et al. 1988

Can. J. Chem.

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adjacent to sulfonyl groups are known to proceed with difficulty, and there is evidence to suggest that these may not necessarily proceed by an SN2 pathway. The mechanism of these reactions could be studied in principle by using the conversion of a-chloro-P-hydroxysulfones of known configuration into a,P-epoxysulfones of known configuration. This paper describes results in which this has been attempted. However, the stereochemical aspects of the epoxide formation could not be assigned unequivocally because of the intervention of a very facile "retro-aldol" process when the chlorohydrins are subjected to treatment with bases, although the experimental results do suggest that the reaction does proceed in a regular SN2-like manner, with inversion at carbon. The X-ray crystal structures of two highly substituted a,P-epoxysulfones are presented, thus putting the structures, including stereochemistry, of a range of these compounds on firm ground. I1 est connu que les riactions de substitution sur des carbones voisins de groupements sulfonyles ne se produisent qu'avec difficult6 et il existe des donnCes sugg6rant que ces r6actions ne precedent pas n6cessairernent par une voie SN2. En principe, on peut 6tudier le rntcanisme de ces reactions en utilisant la transformation d'a-chloro P-hydroxysulfones de configurations connues en a,P-Cpoxysulfones de configurations connues. Dans ce travail, on dCcrit les resultats de telles Ctudes. Toutefois, dfi au fait qu'un processus ccrttro-aldolique~ facile intervient lorsque les chlorohydrines sont soumises a un traitement par les bases, on n'a pas pu attribuer sans equivoque les aspects stCrCochimiques de la formation de I'6poxyde mCme si les rCsultats expkrimentaux suggkrent que la reaction se produit de fait par le biais d'une reaction regulihre SN2, avec inversion au niveau du carbone. On prCsente les structures cristallines dCterminCes par diffraction des rayons-X de deux a,P-Cpoxysulfones fortement substitukes; on Ctablit donc avec certitude les structures, y compris leur stCrCochimie, d'un large Cventail de ces composCs.[Traduit par la revue]

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“…All things considered, D M S O is thought to be the most satisfactory solvent for equilibrium acidity measurements over a wide range of pK (about 30 pK units) with apparently little or no inter ference from ion association effects. Bordwell has accordingly established an absolute scale of acidities in D M S O solution, a portion of which is given as Table 2.3 (Matthews et ai, 1975;Bordwell et al, 1975Bordwell et al, , 1976). …”

Section: Kinetic a N D T H E R M O D Y N A M I C A S S E S S M E N T mentioning

confidence: 99%

Sulfur-Containing Carbanions

1978

Organic Chemistry: A Series of Monographs

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Carbon acids. 13. Acidifying effects of phenylthio substituents

Cited by 102 publications

References 12 publications

Base-Catalyzed Reactivity of Sulfur- and Selenium-Bridged Cyclic Alkynes: Tandem Isomerization and Cycloaromatization versus Isomerization and Nucleophilic Addition

Base-Catalyzed Reactivity of Sulfur- and Selenium-Bridged Cyclic Alkynes: Tandem Isomerization and Cycloaromatization versus Isomerization and Nucleophilic Addition

Stereochemical studies on the formation of α,β-epoxysulfones using α-chloro-β-hydroxysulfones of known configuration

Sulfur-Containing Carbanions

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