| 研究実績の概要 |
The overall goal of this funded research is the development of a bifunctional chiral heterogeneous catalyst for asymmetric tandem oxidative coupling reactions. In our previous work, a simple fabrication method was developed to synthesize a bifunctional catalyst derived from Au/Pd nanoparticles (NPs) and a chiral amine catalyst. However, this catalyst could not be recycled due to the oxidative deactivation of the organocatalyst. As such, in this fiscal year, we began to fabricate a chiral bifunctional heterogeneous catalyst that was derived from chiral phosphoric acids. Since only few examples of heterogeneous chiral phosphoric acids are known, we developed a completely new method to access these organocatalysts and found that this polymer-supported chiral acid catalyst could be used for the asymmetric aza-Friedel Crafts reaction. In addition, we also examined the sequential aerobic oxidation-asymmetric aza-Friedel Crafts reaction with a combined catalyst system composed of heterogeneous Au/Pd NPs and a homogeneous chiral phosphoric acid catalyst. It was found that this system could be used for the asymmetric tandem reaction to furnish the desired products in excellent yields and enantioselectivities. With these results in hand, we are moving towards our final goal of preparing a recyclable chiral bifunctional catalyst.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The progress of this research is going according to our expectations. Although we have yet reached our final target in the first year, all necessary components (preparation of heterogeneous chiral phosphoric acid, demonstration of the viability of asymmetric tandem reaction) are in place to achieve our goal of preparing a recyclable chiral bifunctional heterogeneous catalyst.
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| 今後の研究の推進方策 |
We will continue to follow our course into the fabrication of the chiral heterogeneous bifunctional catalyst as outlined in our original proposal. We are currently scaling-up our optimized synthesis of the chiral phosophoric acid monomer. After this is complete, we will prepare our catalyst according to our previously developed method and we will investigate the substrate scope for the tandem aerobic oxidation-asymmetric aza-Friedel Crafts reaction. In addition, we will perform the recovery and reuse studies in order to demonstrate the recyclability of this bifunctional catalyst. Once our proof-of-concept reaction is completed, we will examine this chiral catalyst for other types of asymmetric oxidative tandem reactions. Finally, we will examine the possibilities of immobilizing other types of organocatalysts to develop a wide range of heterogeneous bifunctional catalysts for tandem asymmetric reactions.
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