Xu X.-H,
Gao R.-T,
Li S.-Y,
Zhou L,
*,
Liu N,
Wu Z.-Q.
*
Hefei University of Technology, Jilin University, Changchun, P. R. of China
Helical Polyisocyanide-Based Macroporous Organic Catalysts for Asymmetric Michael
Addition with High Efficiency and Stereoselectivity.
Chem. Sci. 2024;
15: 12480-12487
DOI:
10.1039/d4sc01316f
Key words
asymmetric catalysis - Michael addition - porous polymers - cycloketones -
trans-nitrostyrenes
Significance
A porous polymer bearing chiral secondary amines (C-poly150) was prepared by polymerizing the homochiral isocyanide monomer using the four-arm
catalyst 4-Pd(II) as the initiator, followed by insertion of the bifunctional isocyanide
crosslinker and subsequent removal of the protecting Boc group, according to equation
1. C-poly150 promoted asymmetric Michael addition of cycloketones with trans-nitrostyrenes in brine at room temperature to give the syn Michael adducts in up to 86% yield and dr ≤ 99:1 with ≤ 99% ee (eq. 2).
Comment
The authors have previously reported linear polymer-catalyzed asymmetric Michael addition
reactions (Macromolecules
2018, 51, 9547). In the Michael addition of cyclohexanone with trans-nitrostyrene, the C-poly150 was recovered by centrifugation and reused five times without significant loss
of its catalytic activity and stereoselectivity.
