RESUMEN
The intramolecular C-H insertions of carbenes derived from 2-diazo-2-sulfamoylacetamides were studied. 2-Diazo-2-sulfamoylacetamides were first prepared from chloroacetyl chloride and secondary amines through acylation followed by sequential treatments with sodium sulfite, phosphorus oxychloride, secondary amines, and 4-nitrobenzenesulfonyl azide. The results indicate that: (1) 2-diazo-N,N-dimethyl-2-(N,N-diphenylsulfamoyl)acetamide can take the formal aromatic 1,5-C-H insertion in its N-phenylsulfonamide moiety to afford the corresponding 1,3-dihydrobenzo[c]isothiazole-3-carboxamide 2,2-dioxide derivative; (2) no aliphatic C-H insertions occur for 2-diazo-2-(N,N-dialkylsulfamoyl)acetamides; and (3) for 2-diazo-N-phenyl-2-(N-phenylsulfamoyl)acetamides, the formal aromatic 1,5-C-H insertion in the N-phenylacetamide moiety is favorable to afford the corresponding 3-sulfamoylindolin-2-one derivatives as sole or major products. The intramolecular competitive aromatic 1,5-C-H insertion reactions of 2-diazo-2-sulfamoylacetamides with aryl groups on both amide and sulfonamide groups reveal that the N-aryl substituents on acetamide are more active than those on sulfonamide. The chemoselectivity is controlled by electronic effect of the aryl group.
Asunto(s)
Acetamidas/química , Compuestos de Diazonio/química , Metano/análogos & derivados , Sulfonamidas/química , Carbono , Catálisis , Hidrógeno , Metano/químicaRESUMEN
Primary alcohols are converted into dialkyl disulfides via heating in situ generated O-alkyl S-difluoro(ethoxycarbonyl)methyl xanthates from ethyl bromodifluoroacetate and potassium xanthates, prepared from primary alcohols and carbon disulfide in the presence of KOH. The reaction mechanism is suggested as an alkyl C[1,3] shift followed by a radical mechanism. This extends to the Chugaev elimination which yields olefins. The current research provides easy access to dialkyl disulfides from commercially available primary alkanols.