A theoretical reexamination of carbanions adjacent to sulfoxide, sulfone and sulfonium centres

Wolfe, Saul; Stolow, Albert; LaJohn, Lawrence A.

doi:10.1016/s0040-4039(00)88264-7

Cited by 77 publications

(43 citation statements)

References 22 publications

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“…The structures of the reactant an< product are shown in 7 and 8 (30). The reaction leads to a 0.2 A decrease in the C-S bond length, and the carbon centre of the ylide 8 is planar, with the HCH plane bisecting the HSH plane.…”

Section: Resultsmentioning

confidence: 99%

“…(30). Deprotonation leads to a 0.136 A shortening of the C-S bond, and the carbon centre of the anion 20 is planar.…”

Section: Ho-+ Ch3sh0mentioning

confidence: 99%

“…An example of such a system is the series of carbanions resulting from the reaction HO-+ CH3X + H 2 0 + -CH2X (X = SR, SOR, S02R, SRzt). Since the structures of these carbanions are known and understood (29,30), it should be possible to predict the relative kinetic acidities of diastereotopic hydrogens adjacent to each of these sulfur-containing moieties. As will be seen, these predictions are in every caseconsistent with experiment.…”

Section: A Qualitative Treatment Of Diastereotopic Selectivitymentioning

confidence: 99%

“…Based on the recent study of -CH2X (X = SH, SMe, SHO, SOMe, S02H, S02Me, 'SH2, %Me2) (29,30), systems with R = H and R = Me exhibit the same trends in their structures and proton affinities. Therefore, R = H was selected for the present study.…”

Section: A Quantitative Treatment Of Diastereotopic Selectivitymentioning

confidence: 99%

“…Therefore, R = H was selected for the present study. The 3-21G* basis set (32) was employed, since this basis set has been found (29,30) the structural effects in these sulfur-containing systems; (3) With R = H, how can a transition structure for proton abstraction from carbon be described, to the exclusion of transition structures for other competing processes? For example, the reaction HO-+ CH3SH2' may proceed by proton abstraction from carbon (to yield the ylide CH,SH,), by proton abstraction from sulfur (to yield CH,SH), or by SN2 displacement on carbon (to yield CH,OH).…”

Section: A Quantitative Treatment Of Diastereotopic Selectivitymentioning

confidence: 99%

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Stereoelectronic effects and the kinetic acidities of diastereotopic hydrogens

Wolfe¹,

Stolow²,

LaJohn³

1984

Can. J. Chem.

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A general qualitative treatment is proposed which accounts for the relative reactivities of diastereotopic hydrogens adjacent to a heteroatom in proton transfer, hydride transfer, and hydrogen atom transfer reactions. This treatment focuses on the structures of the reactive intermediates formed in such reactions, which can be predicted or understood in terms of qualitative molecular orbital arguments, and on the manner in which these intermediates will undergo readdition of H+, H-, or H.. The procedure has been tested, for the specific case of proton transfer reactions, by a direct computational approach to the energy differences between diastereomeric transition states of reactions HO-+ CH3X + H20 + -CH,X (X = sulfide, sulfoxide, sulfone, sulfonium). The computations support the qualitative treatment, and are in all cases in near quantitative agreement with the extensive experimental data concerning the diastereotopic selectivities exhibited in these systems. SAUL WOLFE, ALBERT STOLOW et LAWRENCE A. LAJOHN. Can. J. Chem. 62, 1470(1984. On propose une mCthode qualitative gCntrale qui tient compte des rtactivitts relatives des hydrogknes diastCrCotopiques adjacents i un hCtCroatome lors de rCactions de transfert de protons, d'hydrures ou d'atomes d'hydrogkne. Cette mtthode met l'accent 21 la fois sur la structure des intermidiaires rkactifs formCs au cours de telles rCactions, qui peuvent Ctre prtvus ou compris en termes d'arguments qualitatifs d'orbitales moltculaires, et sur la fa~on dont ces intermtdiaires peuvent subir une nouvelle addition de H' , H-ou He. On a vtrifit cette rnCthode, dans le cas spkcifique de rkactions de transfert de proton, par une technique de calculs directs des diffkrences d'Cnergie entre les Ctats de transition diastCrCoisornkres des reactions: HO-+ CH3X + H20 + -CH2X (X = sulfure, sulfoxyde, sulfone, sulfonium). Les calculs sont en accord avec I'approche qualitative et, dans tous les cas, ils sont aussi en accord quasi-quantitatif avec les donntes exp6rimentales extensives relatives aux sClectivitCs diastCrtotopiques observtes dans ces systkmes.[Traduit par le journal]

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Section: Resultsmentioning

confidence: 99%

“…(30). Deprotonation leads to a 0.136 A shortening of the C-S bond, and the carbon centre of the anion 20 is planar.…”

Section: Ho-+ Ch3sh0mentioning

confidence: 99%

Section: A Qualitative Treatment Of Diastereotopic Selectivitymentioning

confidence: 99%

Section: A Quantitative Treatment Of Diastereotopic Selectivitymentioning

confidence: 99%

Section: A Quantitative Treatment Of Diastereotopic Selectivitymentioning

confidence: 99%

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Stereoelectronic effects and the kinetic acidities of diastereotopic hydrogens

Wolfe¹,

Stolow²,

LaJohn³

1984

Can. J. Chem.

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Chiral Dilithiomethane Derivatives: Structure Determination and Application in Stereoselective Reactions

Müller

2000

Eur. J. Inorg. Chem.

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The synthesis and X‐ray analysis of chiral dilithiomethane analogues derived from sulfoximines are presented. The structures of the sulfoximine‐stabilised mono‐ and dilithio salts have been compared and allow a rationalization of the second lithiation. Organophosphorus‐based dilithiomethane derivatives are also structurally described. The gas‐phase structures of N,S,S‐trimethylsulfoximine 19 and of its mono‐ and dilithiated isomers 20–21 were calculated by ab initio methods employing different levels of theory. For an application in asymmetric synthesis, the dilithiation of (N‐methyl)‐S‐ethyl‐S‐phenylsulfoximine (11) afforded a chiral dinucleophile that undergoes highly regio‐ and stereoselective alkylation reactions with electrophiles. The transmetallation of a chiral dilithiomethane reagent such as 14 with ClTi(OiPr)3 followed by addition of an aldehyde, constitutes a simple one‐pot process for the formation of (E)‐alkenylsulfoximines with excellent diastereoselectivity.

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Effects of sulfenyl, sulfinyl and sulfonyl groups on acidities and homolytic bond dissociation energies of adjacent C?H and N?H bonds

Bordwell¹,

Liu²

1998

J. Phys. Org. Chem.

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Acidities and bond dissociation energies (BDEs) of the N-H bond in two phenylsulfenylamides, PhSNHBz and PhSNH-t-Bu, and four phenylsulfenylanilides, 4-GC 6 H 4 NHSPh, where G = MeO, H, Br and CN, were measured in order to compare the effects of substituents on acidities and BDEs of N-H bonds with those of C-H bonds. The effects of PhS groups on acidities and BDEs in a series of C-H acids were found to be comparable to those on acidities and BDEs of PhS in a similar series of N-H acids. Comparisons were also made of the effects of changing the oxidation state of sulfur in the series PhS, PhSO

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A theoretical reexamination of carbanions adjacent to sulfoxide, sulfone and sulfonium centres

Cited by 77 publications

References 22 publications

Stereoelectronic effects and the kinetic acidities of diastereotopic hydrogens

Stereoelectronic effects and the kinetic acidities of diastereotopic hydrogens

Chiral Dilithiomethane Derivatives: Structure Determination and Application in Stereoselective Reactions

Effects of sulfenyl, sulfinyl and sulfonyl groups on acidities and homolytic bond dissociation energies of adjacent C?H and N?H bonds

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