Chemistry Letters, Vol.47, No.9, 1220-1223, 2018
Synthesis of Cinchona Alkaloid Derived Chiral Squaramide Polymers by ADMET Polymerization and Their Application to Asymmetric Catalysis
The synthesis of cinchona alkaloid-derived chiral squaramide polymers using acyclic diene metathesis (ADMET) polymerization over Hoveyda-Grubbs 2nd generation catalysts (HG(2)) is reported herein. The C3-vinyl group in the cinchona alkaloid easily facilitates the ADMET reaction in the presence of the HG(2) to form a C-C bond. The polymers were subsequently used as catalysts for the asymmetric Michael addition reaction to afford the corresponding chiral products in good yields with excellent stereoselectivities. The catalysts were easily recovered and recycled several times.