Asymmetric epoxidation of styrene and chromenes catalysed by chiral (salen)Mn(III) complexes with a pyrrolidine backbone
2006 (English)In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 237, no 2, 248-254 p.Article in journal (Refereed) Published
A series of chiral (pyrrolidine salen)Mn(III) complexes were synthesized front N-aza-substituted (R,R)-N,N'-bis(3,5-di-tert-butylsalicylidene)-3.4-diaminopyrrolidine salen ligands. High yields and comparable enantioselectivity relative to Jacobsen's catalyst were achieved in asymmetric epoxidation of styrene and chromenes using NaClO/PPNO and m-CPBA/NMO as the oxidant systems. Complexes 1-3, featuring a tertiary airline unit, displayed higher activity than complex 4, bearing ail amide unit and Jacobsen's catalyst in the NaClO/PPNO aqueous/organic biphasic system. The influence of CH3I on epoxidation of 6-nitro-2,2-dimethylchromene catalysed by 1-4 in the biphasic medium was Studied to explore the catalysts with built-in phase-transfer capability. The alkenes' access pathway is discussed on the basis of the steric effect of the N-aza-substituent in the pyrrolidine backbone of complexes 1-3 on the enantioselectivity of epoxidation.
Place, publisher, year, edition, pages
2006. Vol. 237, no 2, 248-254 p.
asymmetric epoxidation, enantioselectivity, pyrrolidine, (salen)Mn(III) complex, unfunctionalized alkenes, active (salen)manganese(iii) complexes, phase-transfer capability, enantioselective epoxidation, nonfunctionalized alkenes, salen complexes, olefins
IdentifiersURN: urn:nbn:se:kth:diva-15423DOI: 10.1016/j.jcat.2005.11.013ISI: 000235330600005ScopusID: 2-s2.0-30144444187OAI: oai:DiVA.org:kth-15423DiVA: diva2:333464
QC 201005252010-08-052010-08-05Bibliographically approved