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SYNFACTS | SYNFACT of the Month 2021-02-02

Polymer-Supported Synthesis

One-Pot Two-Step Catalytic Asymmetric Michael Addition/Hydrogenation

Contributors: Yasuhiro Uozumi, Ryoko Niimi

Chang F, Wang S, Zhao Z, Wang L, Cheng T, Liu G. * Shanghai Normal University, P. R. of China

Enantioselective Dual-Catalysis: A Sequential Michael Addition/Asymmetric Transfer Hydrogenation of α-Nitrosulfone and Enones

ACS Catal. 2020;
10: 10381-10389
DOI: 10.1021/acscatal.0c01559

Key words

dual catalysis - one-pot synthesis - organocatalysis - ruthenium catalysis - asymmetric catalysis - Michael addition

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Significance

A one-pot two-step asymmetric ­Michael addition–transfer hydrogenation co-catalyzed by an immobilized organocatalyst [SA@HSMSN (Cat. A)] and a Ru complex catalyst {[Ru]@HSMSN/HP (Cat. B)} was developed. The reaction of enone and nitro sulfone in the presence of Cat. A,Cat. B, and HCO2Na gave the corresponding alcohols 4 in excellent chemical yields and with high diastereoselectivity (96–99% ee).

Comment

Squaramide and MesRuArDPEN were immobilized in hollow-shell-mesostructured silica nanoparticles without or with a hydrophilic polymer coating to form Cat. A and Cat. B, respectively. Cat. A promoted the Michael addition at –35 °C, and Cat. B catalyzed the transfer hydrogenation at 35 °C, to realize temperature-dependent control of the sequential dual-catalytic process.