Diethyl Tartrate Linked Chiral Macrocyclic Manganese(III)–Salen Complex for Enantioselective Epoxidation of Olefins and Oxidative Kinetic Resolution of Racemic Secondary Alcohols

Abstract

AbstractA diethyl tartrate linked chiral macrocyclic manganese(III)–salen (salen=N,N′‐ethylenebis(salicylimine)) complex has been used for the enantioselective epoxidation of nonfunctionalized alkenes, namely, indene and chromenes, as well as oxidative kinetic resolution of racemic alcohols. For the epoxidation reaction, a 2.5 mol % catalyst loading in the presence of pyridine N‐oxide as an axial ligand and urea–H2O2 adduct as an oxidant gave respective epoxides in high yield (>97 %) and enantiomeric excess (ee, up to 92 %). The same catalyst at a loading of 1.5 mol % has provided enantioenriched (ee up to 97 %) secondary alcohols through oxidative kinetic resolution of racemic alcohols. The catalyst can be recovered and reused up to four times with no loss in performance.