A study of the functional group compatibility of sulfoximination methods

Access to N-cyanosulfoximines by transition metal-free iminations of sulfoxides

Sulfoxides are stereospecifically converted to N-cyanosulfoximines using N-chlorosuccinimide (NCS) as oxidising agent and cyanamide as nucleophilic amine source.

Rhodium-catalyzed direct synthesis of unprotected NH-sulfoximines from sulfoxides

A novel rhodium–catalyzed imination of sulfoxides using O-(2,4-dinitrophenyl)hydroxylamine is developed under mild conditions with good functional group tolerance.

The use of chiral lithium amides in the desymmetrisation of N-trialkylsilyl dimethyl sulfoximines

BACKGROUND

Chiral base desymmetrisation of dimethyl sulfoximines could provide a general route to chiral, enantioenriched dialkyl sulfoximines with potential for use in asymmetric catalysis.

RESULTS

Asymmetric deprotonation of N-trialkylsilyl dimethyl sulfoximines with either enantiomer of lithium N,N-bis(1-phenylethyl)amide in the presence of lithium chloride affords enantioenriched sulfoximines on electrophilic trapping. Ketones, ketimines, trialkylsilyl chlorides and activated alkyl halides may be used as electrophiles in the reaction. Furthermore, a modified Horner-Emmons methodology was investigated.

CONCLUSION

Simple chiral lithium amides afford products with enantiomeric excesses of up to 70%, illustrating that chiral base desymmetrisation of dimethyl sulfoximines is possible.

Comparative Study of Metal-Catalyzed Iminations of Sulfoxides and Sulfides

A comparative study of the imination of sulfur compounds with various metal catalysts in combination with isolated or in situ generated iminoiodinanes (PhI==NR) as nitrogen sources is presented. The influence of the metal catalyst towards the imination of a variety of substituted sulfoxides has been evaluated. Moreover, the effect of the different oxidation states of sulfur on the reactivity and selectivity of the nitrogen transfer redox process in the formation of sulfilimines and sulfoximines was studied. Depending on both the specific metal catalyst as well as the employed nitrene precursor, the sulfide/sulfoxide imination ratio varied in transformations of thianthrene-5-oxide and substituted para-thio phenylsulfoxides.

Iron-Catalyzed Imination of Sulfoxides and Sulfides

[reaction: see text] The Fe(III)-catalyzed imination of sulfoxides and sulfides with sulfonylamides in the presence of iodinanes has been investigated. The best results were obtained when Fe(acac)(3) was used as a catalyst in combination with iodosylbenzene, providing an effective alternative (stereospecific) access to sulfoximines and sulfilimines.