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

• Published in: ChemPlusChem (Weinheim, Germany) Germany), 2014-10, Vol.79 (10), p.1426-1433
• Main Authors: Maity, Nabin Ch, Kumar Bera, Prasanta, Saravanan , S., Abdi , Sayed H. R., Kureshy , Rukhsana I., Khan , Noor-ul H., Bajaj , Hari C.
• Format: Article
• Language: English
• Subjects: alcohols; enantioselectivity; epoxidation; kinetic resolution; manganese; olefins
• ISSN: 2192-6506; 2192-6506
• DOI: 10.1002/cplu.201402131

A 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. Proceed with determination: A diethyl tartrate linked chiral macrocyclic MnIII–salen (salen=N,N′‐ethylenebis(salicylimine); see picture) complex has been used for the enantioselective epoxidation of nonfunctionalized alkenes and for the oxidative kinetic resolution of racemic alcohols.