61937-46-0Relevant academic research and scientific papers
Controlled α-mono- and α,α-di-halogenation of alkyl sulfones using reagent-solvent halogen bonding
Poteat, Christopher M.,Lindsay, Vincent N. G.
, p. 2912 - 2915 (2019/03/17)
The direct and selective α-mono-bromination of alkyl sulfones was achieved through base-mediated electrophilic halogenation. The appropriate combination of solvent and electrophilic bromine source was found to be critical to control the nature of the products formed, where reagent-solvent halogen bonding is proposed to control the selectivity via alteration of the effective size of the electrophilic bromine source. Conversely, the α,α-di-brominated sulfones were selectively obtained in good yields following polyhalogenation followed by selective de-halogenation during workup. Both procedures can be applied on gram scale, and the mono-halogenation was successfully extended to the fully selective α-chlorination, α-iodination and α-fluorination of alkyl sulfones.
Kinetics and mechanism of oxirane formation by darzens condensation of ketones: Quantification of the electrophilicities of ketones
Li, Zhen,Jangra, Harish,Chen, Quan,Mayer, Peter,Ofial, Armin R.,Zipse, Hendrik,Mayr, Herbert
supporting information, p. 5500 - 5515 (2018/05/03)
The kinetics of epoxide formation by Darzens condensation of aliphatic ketones 1 with arylsulfonyl-substituted chloromethyl anions 2 (ArSO2CHCl-) have been determined photometrically in DMSO solution at 20 °C. The reactions proceed v
Ag-catalyzed sulfonylation-peroxidation of alkenes with sulfonyl hydrazides and T-hydro
Xu, Ran,Li, Zhiping
, p. 3942 - 3945 (2018/10/02)
The sulfonylation-peroxidation of alkenes with sulfonyl hydrazides and T-hydro was developed. The Ag-catalyzed three-component peroxidation provides a method for synthesis of a variety of β-sulfonyl peroxides, which could be converted into various sulfone derivatives.
Asymmetric Darzens reaction utilizing chloromethyl phenyl sulfone under phase-transfer catalyzed conditions
Arai, Shigeru,Shioiri, Takayuki
, p. 1407 - 1413 (2007/10/03)
The development of the catalytic asymmetric Darzens reaction utilizing chloromethyl phenyl sulfone is described. The reaction smoothly proceeded to give α,β-epoxysulfones with satisfactory enantioselectivity (up to 83% ee) using chiral quaternary ammonium
Matrix isolation of diphenylsulfene and diphenyl-α-sultine
Sander, Wolfram,Kirschfeld, Andreas,Halupka, Martin
, p. 981 - 986 (2007/10/03)
Diphenylsulfene (5) and diphenyl-α-sultine 6 were generated in cryogenic matrices by three independent routes: (i) the thermal reaction of diphenylcarbene (8) and SO2, (ii) the photochemically induced hetero Wolff rearrangement of sulfonylcarbe
A New Method for the Synthesis of α-Bromoacyl Silanes via Ring-opening of 2-Phenylsulphonyl-2-trimethylsilyloxiranes
Hewkin, Cheryl T.,Jackson, Richard F. W.
, p. 3103 - 3112 (2007/10/02)
2-Phenylsulphonyl-2-trimethylsilyloxiranes 2 are efficiently prepared by treatment of 2-phenyl-sulphonyloxiranes 3 with butyllithium in the presence of chlorotrimethylsilane at low temperatures.Reaction of 3-alkyl-2-phenylsulphonyl-2-trimethylsilyloxiranes 2, in which the alkyl group is primary, with magnesium bromide at room temperature gives 2-bromoacyl silanes 1 in good yield.Reaction at higher temperatures leads to competing formation of bromovinyl sulphones 7.Reaction of 3,3-dialkyloxiranes with magnesium bromide occurs much more readily, leading to 2-bromoacyl silanes 1 in moderate yields.Other products derived from a common carbocationic intermediate are also isolated.
PREPARATION AND RING-OPENING REACTIONS OF 2-PHENYLSULPHONYL-2-TRIMETHYLSILYL OXIRANES
Hewkin, Cheryl T.,Jackson, Richard F. W.
, p. 1877 - 1880 (2007/10/02)
Reaction of 2-phenylsulphonyl oxiranes (1) with butyllithium in the presence of chlorotrimethylsilane gave 2-phenylsulphonyl-2-trimethylsilyl oxiranes (2), which on treatment with MgBr2*Et2O gave 2-bromoacylsilanes (3) and either bromovinyl sulphones (5)
Stereochemical studies on the formation of α,β-epoxysulfones using α-chloro-β-hydroxysulfones of known configuration
Grossert, J. Stuart,Sotheeswaran, Subramanian,Dharmarante, H. Ranjith W.,Cameron, T. Stanley
, p. 2870 - 2879 (2007/10/02)
Substitution reactions 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 α-chloro-β-hydroxysulfones of known configuration into α,β-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 α,β-epoxysulfones are presented, thus putting the structures, including stereochemistry, of a range of these compounds of firm ground.
A stereocontrolled approach to electrophilic epoxides
Meth-Cohn, Otto,Moore, Clive,Taljaard, Heinrich C.
, p. 2663 - 2674 (2007/10/02)
Lithium t-butyl hydroperoxide (easily generated by addition of an alkyl-lithium to anhydrous t-butyl hydroperoxide in THF solution) is a powerful reagent for the epoxidation of electrophilic alkenes at -20 to 0 °C under full stereocontrol. Thus αβ-unsaturated esters, sulphones, sulphoximines, and amides are readily epoxidised with complete regio- and stereo-specificity and with considerable chiroselectivity (20-100%) when appropriate chiral auxiliaries such as menthyl, 8-phenylmenthyl, or a camphor-sulphonamide derivative are used. Asymmetric αβ-unsaturated sulphoximines undergo epoxidation with 100% diastereoselectivity. The only exceptions to stereocontrol noted are heavily substituted maleate esters such as di-t-butyl maleate. The αβ-epoxy amides are shown to be valuable sources of the corresponding epoxy ketones by treatment with an organolithium, allowing a stereo- and chemoselective entry in high yield to these useful intermediates.
A Powerful New Stereo-controlled Method for Epoxidation of Electrophilic Alkenes
Clark, Carol,Hermans, Patricia,Meth-Cohn, Otto,Moore, Clive,Taljaard, Heinrich C.,Vuuren, Gerda van
, p. 1378 - 1380 (2007/10/02)
t-Butyl hydroperoxide and an alkyl-lithium in dry tetrahydrofuran are shown to epoxidise α,β-unsaturated esters and sulphones efficiently in a stereo- and regio-specific manner, while esters of chiral alcohols undergo diasterefacially selective epoxidatio
