Design of main-chain polymers of chiral imidazolidinone for asymmetric organocatalysis application

Abstract

Main-chain polymers of chiral imidazolidinone were successfully synthesized by reaction of chiral imidazolidinone dimers with disulfonic acid. Chiral imidazolidinones were incorporated into the main-chain of the polymer by ionic bonding. These polymers could be used as polymeric chiral organocatalysts for asymmetric Diels-Alder reactions.

Synthesis of Main‐Chain Ionic Polymers of Chiral Imidazolidinone Organocatalysts and Their Application to Asymmetric Diels–Alder Reactions

“…A main‐chain ionic polymer of tyrosine‐derived chiral imidazolidinone 4 was synthesized as shown in Scheme . A chiral imidazolidinone dimer 3C was prepared according to the process described in our previous report . A series of main‐chain ionic polymers 4 were synthesized by the polyaddition reaction of chiral imidazolidinone dimer with butenylene spacer 3C and a selected series of disulfonic acids 5 in a CH 2 Cl 2 /H 2 O biphasic solvent system.…”

“…The effect of the chiral imidazolidinone spacer of main‐chain ionic polymers 4Ae to 4Ee on the catalytic activity has been investigated in our previous report. We found that the main‐chain polymer of chiral imidazolidinone with the butenylene spacer 4Ce exhibited excellent catalytic activity . First, the effect of the disulfonate structure on the catalytic activity was investigated.…”

“…Importantly, a few of these main‐chain polymers exhibit higher enantioselectivity than that of model organocatalysts when tested in asymmetric reactions . Despite the importance of tuning the structure of the main‐chain repeat unit, the influence of chiral imidazolidinone dimers and disulfonate components in main‐chain polymers of chiral imidazolidinone salts on asymmetric reactions has not been comprehensively investigated . Appropriately designed main‐chain polymeric chiral organocatalysts can provide a suitable microenvironment for asymmetric reactions and often show high stereoselectivity.…”

Chiral anion-triggered helical poly(ionic liquids)

“…1,2 Inspiring from nature most of the researchers concentrating on synthesis of chiral polymers for different applications. The synthetic chiral polymers elegantly combine the advantages of both chiral interfaces and traditional polymers, affording wide range of applications such as, catalysts in various kinds of asymmetric reactions, 3,4 biointerface materials, 5 PH responsive materials, 6 chiral separations, 7 chiral sensors 8 etc. In recent years, the design and synthesis of helical polymers with a controlled helixsense have attracted significant attention for its possible applications like sensing, separation of enantiomers, enantioselective catalysis etc.…”

Synthesis of MacMillan catalyst modified with ionic liquid as a recoverable catalyst for asymmetric Diels–Alder reaction

“…27 Pecinovsky et al developed a nanoporous heterogeneous chiral catalyst via acidinduced liquid crystal self-assembly and subsequent photopolymersiation of monomer of imidazolidinone unit. 31 Mitsudone et al also supported MacMillan catalyst on montmorillonite clay using cation exchange method. 29 Haraguchi et al used polymer supported sulphonic acid for immobilization of MacMillan catalyst by ionic interaction via ion exchange between sulfonated polymer and quaternary ammonium salt.…”