Two new chiral calixarene-salen ligands 1a,b, based on calixarene platforms in 1,3-alternate conformation, have been prepared by a new general synthetic pathway. Their Mn(III) complexes, 3a,b, have shown fairly good efficiency in the asymmetric epoxidation of styrene and substituted styrenes, whereas excellent catalytic activity and selectivity were observed with rigid bicyclic alkenes, namely 1,2-dihydronaphthalene and substituted 2,2’-dimethyl-chromene. The higher catalytic properties of 3a may be ascribed to the more rigid and inherently chiral structure as proved by molecular modelling, NMR spectroscopy and X-ray data of the similarly structured UO2 complexes 2a,b.
|Titolo:||Novel Chiral (Salen)MnIII Complexes Containing a Calixarene Unit in 1,3- alternate conformation as Catalysts for Enantioselective Epoxidation Reactions of (Z)-Aryl Alkenes|
|Data di pubblicazione:||2014|
|Appare nelle tipologie:||1.1 Articolo in rivista|