Selective synthesis of primary methoxypropanol using clay supported tris(2,4-pentanedionato)zirconium(IV)

Ring-Opening of Oxiranes using Taeniolite-Supported Tris(β-Diketonato)Zirconium

“…The data show that the ring-opening reaction of methyl oxirane was independent of the type of alcohol when 2a/TN was employed in the reaction. This was likely due to a desolvation property inside the Taeniolite layers, which consequently enhanced the Lewis acidity of the complex, as it was poorly solvated [3,27,28]. Such a property is uniquely important because the same reaction with bulky nucleophiles demonstrates a considerably lower activity when catalyzed by the homogeneous counterparts ( …”

“…The synthetic route for such compounds commonly proceeds via ring-opening of oxiranes (epoxides) using traditional Lewis acids such as Cu(BF 4 ) 2 [2,21], Sn(OTf) 2 [11], BF 3 [22], Sc(OTf) 3 [24], and traditional solid acids such as amberlyst-15 [10]. Modified Lewis acid complexes based on salen [5,12] and porphyrin [23] ligands have also been reported.…”

“…An alternative reaction method using a microwave technique has also been examined [13], even though such a method still experiences difficulties in scale-up processes. In continuation of our research on oxirane ring-opening reactions [3,7,8] we report herein a new methodology for oxirane ring-opening using clay-supported Zr(IV) diketonates. The clay selected as a host was lithium Taeniolite, denoted as Li-TN [26].…”

“…Lewis acidity at the metal center in the complex was improved by utilization of phenyl and fluoro diketone ligands and was observed from its homogeneous state [7,8]. We have previously discussed an immobilization effect of a zirconium complex into clays [3,8] and observed the enhancement in catalytic activities likely due to a desolvation phenomenon of metal complexes in clay layers [27,28]. We have also observed a selectivity enhancement when a zirconium complex was immobilized into Taeniolite and natural Bentonite, which was possibly due to constrained clay layers (the clays were notably swollen poorly in alcohols) [3].…”

“…We have previously discussed an immobilization effect of a zirconium complex into clays [3,8] and observed the enhancement in catalytic activities likely due to a desolvation phenomenon of metal complexes in clay layers [27,28]. We have also observed a selectivity enhancement when a zirconium complex was immobilized into Taeniolite and natural Bentonite, which was possibly due to constrained clay layers (the clays were notably swollen poorly in alcohols) [3]. In this work, we found that the trend in the selectivity of the heterogeneous catalysts was, unlike that of the homogeneous catalysts, independent on the functional groups of ligands, and the activity of the heterogeneous catalysts was dependent on the size of the substrate.…”