Two new chiral calix[4]arene-salen ligands 1a,b, based on calix[4]arene 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.
Novel Chiral (Salen)MnIII Complexes Containing a Calix[4]arene Unit in 1,3- alternate conformation as Catalysts for Enantioselective Epoxidation Reactions of (Z)-Aryl Alkenes
BONACCORSO, CARMELAPrimo
;BALLISTRERI, Francesco Paolo;PAPPALARDO, ANDREA;TOMASELLI, Gaetano;TOSCANO, Rosa Maria;SCIOTTO, Domenico
Ultimo
2014-01-01
Abstract
Two new chiral calix[4]arene-salen ligands 1a,b, based on calix[4]arene 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.File | Dimensione | Formato | |
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16- Dalton Transaction 2014.pdf
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