Manganese Complexes for Alkene Oxidation Based on Pyridyl Ligands

3 Manganese Complexes for Alkene Oxidation Based on Pyridyl Ligands 

A drawback associated with the l,4,7-trimethyl-l,4,7-triazacydononane based catalyst is the often tedious procedure to achieve modifications of the ligand 

High epoxidation activity was found for manganese complexes based on dinucleating ligand N,N,N, N -tetrakis(2-pyridylmethyl)-l,3-propanediamine (tptn) [132]. The ligand contains a three-carbon spacer between the three-N-donor sets. This type of ligand is readily accessible, and facile modification of the ligand structure can be achieved. Complexes of this type have also been reported as mimics for PSII [131]. 

High selectivity was observed in the epoxidation of cyclic alkenes (especially cydohexene) with the important feature that allylic oxidation products were not obtained. Excellent results are reported for internal alkenes, for example, trans-2-octene and trans-4-octene, whereas terminal linear alkenes give slightly lower yields. 

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