N=S Bond Formation
A rhodium-catalyzed transfer of carbamates to sulfoxides enables a convenient synthesis of N-protected sulfoximines under mild conditions. Sulfoximines, including 4-membered thietane-oximines, bearing Boc and Cbz groups are readily deprotected.
M. Zenzola, R. Doran, R. Luisi, J. A. Bull, J. Org. Chem., 2015, 80, 6391-6399.
In a preparation of N-alkyl-substituted sulfoximines from sulfides, in situ generated N-bromoalkylamines serve as readily accessible imidating agents leading to N-alkylsulfiliminium bromides that are subsequently oxidized providing the desired products. This unprecedented one-pot imidation/oxidation sequence provides gram quantities of product in a short period of time avoiding the use of toxic alkylating reagents.
C. A. Dannenberg, V. Bizet, C. Bolm, Synthesis, 2015, 47, 1951-1959.
The synthesis of N-cyanosulfilimines can readily be achieved by reaction of the corresponding sulfides with cyanogen amine in the presence of a base and NBS or I2 as halogenating agents. Oxidation followed by decyanation affords synthetically useful sulfoximines.
O. García Mancheño, O. Bistri, C. Bolm, Org. Lett., 2007, 9, 3809-3811.
|Sulfoximines, sulfilimines, sulfinimides, sulfonimidates and sulfonimidamides - the chiral sulfur connection|