Regioselective Mono‐ and Bis‐Sulfenylation of Active Methylene Compounds

Abstract

Selective mono-and bis-sulfenylation of active methylene groups with a variety of disulfides at an ambient temperature is reported. Sulfenylation is promoted by iodine as a catalyst and sulfenyl iodides as intermediates, under metal-

Towards the Iodine‐Catalyzed Regioselective Sulfenylation of Unsymmetrical Ketones

“…Taking our earlier report on the regioselective mono‐ and disulfenylation of active methylene compounds as a reference, we tried to sulfenylate unsymmetrical ketones under the same reaction conditions. However, the ketones exhibited anomalous behavior and did not give the desired products.…”

“…Thus, 26 examples of monosulfenylated derivatives 3aa – fd were synthesized efficiently (Table ). In the case of 2‐butanone, over‐sulfenylation was expected because of the higher acidity of the α‐methine proton adjacent to the sulfenyl group . However, after the addition of more than 2 equivalents of base, no over‐sulfenylated product was obtained.…”

Sulfenylation of C–H Bonds for C–S Bond Formation under Metal‐Free Conditions

“…Hydrogen iodide can readily be oxidized by DMSO to yield iodine and dimethylsulfane. [17a] Mono‐ and disulfenylation of active methylene compounds with a variety of disulfides by use of the I 2 /DMSO system was also disclosed by Barman et al…”

Ultrasound Assisted Solvent/Metal Free Synthesis of 3‐Sulfenylindoles Employing TBATB‐Grafted MCM‐48 as a suitable Heterogeneous Catalyst.

“…Recently Ashish R. Das and his group established magnetically recyclable nano nickel ferrite catalyzed one-pot chalcogenation of bioactive heterocycles under aerobic condition. [37] In this manuscript, synthesis of 3sulfenylindoles in a solvent/metal free ultrasonication by catalytic action of TBATB/MCM-48 is reported. Compared to conventional heating process, this ultrasonication technique is much faster and efficient to effect ability of the reaction.…”

“…A number of metal or non‐metal‐grafted MCM‐48 reportedly acted as excellent catalyst in organic transformations, although selective sulfenylation of C−H bond is never known. Recently Ashish R. Das and his group established magnetically recyclable nano nickel ferrite catalyzed one‐pot chalcogenation of bioactive heterocycles under aerobic condition . In this manuscript, synthesis of 3‐sulfenylindoles in a solvent/metal free ultrasonication by catalytic action of TBATB/MCM‐48 is reported.…”