Iron and Ruthenium Glycoporphyrins: Active Catalysts for the Synthesis of Cyclopropanes and Aziridines

In view of the relevance of cyclopropanes and aziridines as synthetic building blocks as well as active parts in biological and pharmaceutical compounds, the development of sustainable synthetic procedures for obtaining these products continues to be a significant challenge. Herein, we report the synthesis of iron and ruthenium glycoporphyrins and their catalytic activity in promoting cyclopropanations and aziridinations by using diazo compounds and aryl azides as carbene and nitrene precursors, respectively. The number and location of carbohydrate units on the porphyrin skeleton modulated the shape- and diastereoselectivity of the reactions. Interestingly, while iron(III) glycoporphyrins showed good performances in alkene cyclopropanations, ruthenium(II) complexes performed better in aziridination reactions. Although none of the reported complexes induced enantiocontrol, probably due to the long distance between the chiral carbohydrate and the active metal center, excellent trans-diastereoselectivities were observed by using iron-glycoporphyrins as cyclopropanation promoters.