Asymmetric Michael Addition Catalyzed by a Polyisocyanide-Based Porous Polymer

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.

Publication History

Article published online:
16 October 2024