Carbon-13 nuclear magnetic resonance spectral properties of alkyl disulfides, thiolsulfinates, and thiolsulfonates

Bass, S. Woody; Evans, Slayton A.

doi:10.1021/jo01292a032

Cited by 55 publications

(25 citation statements)

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“…The occurrence of some [α‐D] 3 mentioned above can be understood through a very slow reaction of DCl (first column of Scheme ) with acid 3 (as formed in step 3), in analogy with the labeling technique reported25,26 for a related system. During storage of the mixture for some weeks at ambient temperature without workup, the sulfoxide 12 vanished slowly, with appearance27 of H 3 CS–SO 2 CH 3 24a,24c. The ester 4 is probably not generated under the reaction conditions shown in Scheme from the intermediates 6 or 8 (in contrast to Scheme ), presumably due to a shortage of bases such as 7 in this HCl‐producing system; this notion gained support in the following way: A sample (5 mg) of pure ester 4 was added to this aged solution and required significantly longer than 4 h at 55 °C for its cleavage by HCl to give 11 (2nd column of Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Acylation Mechanisms of DMSO/[D₆]DMSO with Di‐tert‐butylketene and Its Congeners

Knorr

2011

Eur J Org Chem

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Dimethyl sulfoxide (DMSO) and tBu 2 C=C=O in diglyme require heating to about 150°C to furnish the Pummerer-type product tBu 2 CHCO 2 CH 2 SCH 3 through a novel mechanistic variant. The "ester enolate" tBu 2 C=C(O -)-O-S + (CH 3 ) 2 arising through the reversible addition of DMSO (step 1) to C-1 of tBu 2 C=C=O must be trapped through protonation (step 2) at C-2 by a carboxylic acid catalyst to form tBu 2 CH-C(=O)-O-S + (CH 3 ) 2 so that the reaction can proceed. The ensuing cleavage (step 3) of the O-S bond and one of the C-H bonds in the -S(CH 3 ) 2 group (E2 elimination, no ylide intermediate) results in the formation of tBu 2 CHCO 2 -and H 3 CS-CH 2 + , whose combination (step 4) generates the final product. With a mixture of DMSO and [D 6 ]DMSO competing for tBu 2 C=C=O in diglyme, the small value of the kinetic H/D isotope effect (KIE) k H /k D = 1.26 at 150°C indicates that the cleavage of the C-H/C-D bonds (step 3) does not occur in the transition state with the highest free enthalpy. Therefore, the practically isotope-independent steps 1 and 2 determine

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Section: Resultsmentioning

confidence: 99%

Acylation Mechanisms of DMSO/[D₆]DMSO with Di‐tert‐butylketene and Its Congeners

Knorr

2011

Eur J Org Chem

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“…The product was identified based on the published 1 H and 13 C NMR spectroscopic data. [27,34] 4,4-Dimethyl-1,2-diselenolane [28] (4d): Selenium (200 mesh; 4.12 g, 52.2 mmol), powdered NaOH (3.13 g, 78.3 mmol), and 50 mL of dmf were placed into a 100-mL two-necked flask equipped with a magnetic stir bar (under argon) and 0.71 mL of 100 % hydrazine hydrate (14.6 mmol) was added slowly (over 30 min using a syringe pump). After nitrogen evolution had ceased a dark brown solution was obtained.…”

Section: 2-dithianementioning

confidence: 99%

Catalyst Leaching as an Efficient Tool for Constructing New Catalytic Reactions: Application to the Synthesis of Cyclic Vinyl Sulfides and Vinyl Selenides

et al. 2009

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Catalyst leaching from Pd and Ni particles stabilized by organic sulfur and selenium ligands occurs in solution in the presence of phosphanes. This process has been monitored in real time by 1D and 2D NMR spectroscopy and the nature of the metal species established. This catalyst leaching is shown to be a powerful tool for generating new catalytic activity from species formed in situ where the parent bulk particles

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“…Bass and Evans show that yk0, effects are slightly deshielding for C-a, and that the angle between C-w-0-SO2-C-a appears to be the critical factor contributing to differences in back donation. 26 As back donation increases, the ybo, shielding effect is reduced and the signal appears downfield. The conformations of 1 and 2 are shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

¹³C NMR of organosulfur compounds the ¹³C chemical shifts of monocyclic γ‐ and δ‐sultones

Smith

Wolinsky

1982

Org. Magn. Reson.

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The 13C NMR spectra of several monocyclic y-sultones(l,2-oxatane 2,240xides) and S-sultones(l,2-oxathiane 2,2-dioxides) have been determined and are presented herein. "he chemical shifts of the ring carbons of these compounds are compared in terms of conformational, electronic and anisotropic Merences. Electric field effects may be responsible for the chemical shifts of the C-w carbon, but do not appear to be important for C-a. Anisotropic deshielding also appears to be important for the chemical shats of C-0, but the effects on C-or appear to be small. Dipole changes at C-a and C-w, induced by back donation of electron density from the ring oxygen to sulfur, may explain the chemical shifts at C-cw. Substituent effects are readily explained in terms of well-known effects. In general, the carbons closest to the sulfonate group are found to be the most affected, and the carbons of the S-sdtones proximate to the sulfonate group are found to be more deshielded than those of the y-sultones.Interest in organosulfur compounds as useful synthetic intermediates has grown in recent years, and several reports have examined the 13C NMR spectra of these compounds.'-6 Sultones, however, had not been studied for their synthetic utility until our recent investigation.' As part of this study we recorded the 13C NMR spectral data for a number of y -and 6-s~l t o n e s .~ The 13C chemical shifts for propane sultone (l), butane sultone (2) and a number of unsaturated sultones known as pysultones( 1,2-oxathiin 2,2-dioxides), 11, have been previously reported, but these spectra were not discussed in detaiL4 RESULTSThe 13C chemical shifts for the ring carbons of the monocyclic y-and 6 -sultones, 1-22, of general structure I, are listed in in the 6-membered ring series relative to the five finds precedent in other saturated heterocyclic compounds these compounds contain two functional groups (and/or heteroatoms) in the ring and bear exocyclic oxygens. The downfield shift is 4.68 ppm for sultones 1 and 2, 3.25ppm for sultams 23 and 24; and 11.8 ppm for lactones 25 and 26.9 An examination of sultones in Table 1 (I, n = 0) indicates that substitution at C-a induces changes in the C-o signal in the range -1.71 to +2.73ppm relative to 1. This variation is probably due to conformational changes in the 5-membered ring, induced by the different substituents.The 6-membered ring sultones 9 and 10 show a 5 ppm downfield shift relative to 2, although this may be partially due to the 'beta-effect' described by Grant and for alkyl substitution. A more dramatic example of changes in the C-o signal due to conformational changes is observed with the bicyclic sultones 21 and 22. The C-o carbon signal of 21 and 22 is 13.25 and 16.6 ppm downfield, respectively, relative to 1, and the E isomer 22 is 3.35 ppm downfield of the Z isomer 21. It is likely that the shift difference between 1 and 2 is the result of conformational differences, but it is not clear if the effect is due to anisotropy, electric field effects or induced dipole changes of reported in th...

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Carbon-13 nuclear magnetic resonance spectral properties of alkyl disulfides, thiolsulfinates, and thiolsulfonates

Cited by 55 publications

References 6 publications

Acylation Mechanisms of DMSO/[D₆]DMSO with Di‐tert‐butylketene and Its Congeners

Acylation Mechanisms of DMSO/[D₆]DMSO with Di‐tert‐butylketene and Its Congeners

Catalyst Leaching as an Efficient Tool for Constructing New Catalytic Reactions: Application to the Synthesis of Cyclic Vinyl Sulfides and Vinyl Selenides

¹³C NMR of organosulfur compounds the ¹³C chemical shifts of monocyclic γ‐ and δ‐sultones

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Carbon-13 nuclear magnetic resonance spectral properties of alkyl disulfides, thiolsulfinates, and thiolsulfonates

Cited by 55 publications

References 6 publications

Acylation Mechanisms of DMSO/[D6]DMSO with Di‐tert‐butylketene and Its Congeners

Acylation Mechanisms of DMSO/[D6]DMSO with Di‐tert‐butylketene and Its Congeners

Catalyst Leaching as an Efficient Tool for Constructing New Catalytic Reactions: Application to the Synthesis of Cyclic Vinyl Sulfides and Vinyl Selenides

13C NMR of organosulfur compounds the 13C chemical shifts of monocyclic γ‐ and δ‐sultones

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Acylation Mechanisms of DMSO/[D₆]DMSO with Di‐tert‐butylketene and Its Congeners

Acylation Mechanisms of DMSO/[D₆]DMSO with Di‐tert‐butylketene and Its Congeners

¹³C NMR of organosulfur compounds the ¹³C chemical shifts of monocyclic γ‐ and δ‐sultones