Encapsulated Cobalt-Porphyrin as a Catalyst for Size-Selective Radical-type Cyclopropanation Reactions

A cobalt-porphyrin catalyst encapsulated in a cubic M8L6 cage allows cyclopropanation reactions in aqueous media. The caged-catalyst shows enhanced activities in acetone/water as compared to pure acetone. Interestingly, the M8L6 encapsulated catalyst reveals size-selectivity. Smaller substrates more easily penetrate through the pores of the molecular ship-in-a-bottle catalysts and are hence converted faster than bigger substrates. In addition, N-tosylhydrazone sodium salts are easy to handle reagents for cyclopropanation reactions under these conditions.