Iodinane- and Metal-Free Synthesis of N-Cyano Sulfilimines: Novel and Easy Access of NH-Sulfoximines
Olga García Mancheño, Olivia Bistri and Carsten Bolm*
*Institute of Organic Chemistry, RWTH Aachen University,
Landoltweg 1, D-52056 Aachen, Germany, Email: carsten.bolm
oc.rwth-aachen.de
O. García Mancheño, O. Bistri, C. Bolm, Org. Lett., 2007, 9, 3809-3811.
DOI: 10.1021/ol7016577
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Abstract
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.
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General procedures for the imination with H2NCN:
To a solution of sulfide (1.0 mmol), H2NCN (55.0 mg, 1.3 equiv) and tBuOK (135.0 mg, 1.2 equiv) in MeOH (6 mL) at room temperature, NBS (267.0 mg, 1.5 equiv.) was added. Once the starting material was consumed (monitored by TLC), the reaction mixture was concentrated under reduced pressure, saturated aqueous Na2S2O3 was added and extracted with CH2Cl2 (3 x 5 mL). The organic layer was dried over anhydrous MgSO4, filtered and evaporated. The residue was purified by flash column chromatography.
General procedures for the synthesis of N-cyano sulfoximines:
To a stirred solution of sulfilimine 2 (1.0 mmol) in EtOH (10 mL), K2CO3 (414.0 mg, 3.0 mmol) and m-CPBA (ca. 70%; 370.0 mg, 1.5 mmol) were added at 0 ºC. Then, the mixture was allowed to react at room temperature until the starting material was consumed (monitored by TLC). The solvent was removed under reduced pressure, water was added and the resulting mixture was extracted with CH2Cl2 (3 x 8 mL). The organic layer was dried over anhydrous MgSO4, filtered and evaporated. The residue was purified by flash column chromatography.
General procedure for the synthesis of NH-sulfoximines
To a stirring solution of sulfoximine 4 (1.0 mmol) in CH2Cl2 (18 mL) at 0 °C was added TFAA (417.0 µL, 3.0 mmol). Then, the mixture was allowed to react at room temperature until the starting material was consumed (monitored by TLC). The reaction mixture was concentrated, diluted in MeOH (7 mL) and treated with K2CO3 (691.0 mg, 5.0 mmol). The mixture was allowed to react at room temperature until the starting material was consumed (monitored by TLC). The solvent was removed under reduced pressure and the residue was purified by flash column chromatography.
Key Words
Imination, Sulfoximines, Sulfilimines, NBS, MCPBA
ID: J54-Y2007-3010
