The Development Of PDMS Sponge Supported Organic Catalysts And Ligands And Their Applications In Catalytic Organic Reactions

In the past,the excellent organic synthetic chemists have synthesized a large number of complex products through straightforward and even rude methods.However,with the outbreak of environmental problems and the resource and energy awareness has risen.In 1991,under the advocacy and leadership of Paul T.Anastas,“Green Chemistry” was born.For synthetic chemists,it is necessary to shift the focus of synthesis from “what to synthesize” to “how to synthesize” for adapting to the strategic direction of sustainable development,and catalysis as the most important way in organic synthesis,it is natural to start from here to find a new,efficient and clean green catalytic synthesis strategy.Among them,a feasible solution is to immobilize them onto insoluble solid support materials,so that these catalysts can be recycled and reused.Based on above,the successfully developed polydimethylsiloxane(PDMS,a stable and hydrophobic polymer material)sponge supported 4-dimethylaminopyridine(DMAP),(1S,2S)-(+)-1,2-diaminocyclonhexane(or(1R,2R)-(-)-1,2-diaminocyclonhexane)and L(+)-Cysteine can be directly used as base catalysts and ligands to participate in organic reactions.Other chiral catalysts and ligands can also be formed by further derivatization,and coordination with salts of the metals such as copper,gold and cobalt to form more complex PDMS sponge-chiral metal catalysts.The synthetic monitoring,morphology and content analysis of PDMS sponge-DMAP were carried out by related material characterization methods.Then PDMS sponge-organic base catalyst was used to promote a series of organic conversion,the wide range of substrate applications,excellent yields,and high morphological enantiomeric excess(ee)demonstrate that PDMS sponge-organic base catalysts have high catalytic efficiency and reusability in water.It also proves the universality of PDMS sponge-organic base catalyst,which can promote so many organic conversions in water.Among them,the structure of the related reaction products was characterized by nuclear magnetic resonance and single crystal diffraction.The relevant reaction yield and ee were quantitatively analyzed by gas chromatography(GC)and high performance liquid chromatography(HPLC).And from relevant control experiments,the PDMS sponge-DMAP provides better catalytic activity and selectivity than free DMAP in water.And from the relevant control experiments,this PDMS sponge DMAP can provide much better catalytic activities and selectivities than free DMAP in water.Through an easy-to-build continuous flow reactor,the PDMS sponge DMAP facilitated reactions can be facilely scaled up.Similarly,the derivatized PDMS sponge-chiral metal catalysts and PDMS sponge-photocatalysts have also been initially explored and validated.At last,we believe that this porous hydrophobic PDMS sponge material will be a promising carrier for the development of highly efficient recyclable catalysts in water.