(1R,2R)-(+)-1,2-DPEN-modified Wang resin: An efficient catalyst for the asymmetric Michael addition of acetone to β-nitroolefins

• Heterogeneous catalyst was achieved via simple N-acylation reaction.
• This heterogeneous catalyst presented satisfied results.
• The catalytic mechanism was investigated through XPS.
• Continuous reaction was realized in a fixed-bed reactor with this catalyst.

Wang resin was modified by (1R,2R)-(+)-1,2-DPEN by means of a triazine ring. The catalyst was characterized by thermogravimetric (TG) analysis, elemental analysis, and Fourier transform infrared spectroscopy (FT-IR). Subsequently, this catalyst was employed for the asymmetric Michael addition of acetone to β-nitrostyrene. Under optimized conditions, 76.6% of β-nitrostyrene conversion and 82.8% enantioselectivity of Michael adduct were obtained. On the basis of the characterization of the catalyst by X-ray photoelectron spectroscopy (XPS), the mechanism of catalysis was proposed. In addition, the generality of the catalyst was evaluated with Michael additions of acetone to β-nitroolefins. Finally, the continuous reaction was realized in a fixed-bed reactor.

Mechanism of Michael addition of acetone to β-nitrostyrene over the catalyst with acetic acid.Figure optionsDownload as PowerPoint slide