Highly specific N-monomethylation of primary aromatic amines

A synthetic methodology for the specific conversion of primary aromatic amines into their N-monomethyl derivatives under very mild conditions is presented. Anilines are treated with 4-nitrobenzenesulfonyl (nosyl) chloride to generate the corresponding sulfonamides 2 in high yields. The subsequent N-methylation reaction of the sulfonamides 2 with a solution of diazomethane is rapid and quantitative. Removal of the nosyl protecting group is readily carried out using the reagent system mercaptoacetic acid/1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) affording the N-monomethylated aromatic amines 4. The procedure is convenient, efficient, and gives rise to the N-monomethyl-anilines exclusively.     

Rhodium perfluorobutyramide (Rh2(pfm)4): a synthetically useful catalyst for olefin aziridinations

Rhodium perfluorobutyramide (Rh₂(pfm)₄) has been shown to catalyze the conversion of olefins to trichloroethoxysulfonyl, nosyl, and tosyl aziridines. Advantages of this aziridination procedure include the microwave-assisted preparation of the catalyst and the practical use of the alkene substrate as the limiting reagent.