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The features of various anions having different soft/hard character (aliphatic and aromatic amines, alcohoxydes, phenoxides, thiolates) are compared with regard to nucleophilic substitutions on dimethyl carbonate (DMC), using different reaction conditions. Results are well in agreement with the Hard-Soft Acid-Base (HSAB) theory. Accordingly, the high selectivity of monomethylation of CH 2 acidic compounds and primary aromatic amines with DMC can be explained by two different subsequent reactions, which are due to the double electrophilic character of DMC. The first step consists of a hard-hard reaction and selectively produces a soft anion, which, in the second phase, selectively transforms into the final monomethylated product, via a soft-soft nucleophilic displacement (yield >99% at complete conversion, using DMC as solvent).

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Different Iron (III) species were used as catalysts in sulfoxidation reactions giving excellent yields and high chemoselectivity. Among the iron (III) species, the best one was a solid b-cyclodextrin-FeBr 3 complex. Sulfoxidation takes place with high chemoselectivity in the presence of other groups such as isothiocyanate. Good results were obtained when these reactions were analyzed using green chemistry metrics.