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2.3.4.1.4 α,β-Unsaturated Carbonyl Acceptors and α-Nitro Carbonyl Donors

DOI: 10.1055/sos-SD-215-00165

Geertsema, E. M.; Poelarends, G. J.Science of Synthesis: Biocatalysis in Organic Synthesis, (20152319.

There are two examples of enzyme-catalyzed Michael additions of α-nitro carbonyl donors 10 to an α,β-unsaturated carbonyl acceptor (Scheme 4).[‌54‌] Monitoring of numerous immobilized lipases for Michael addition activity with the donor methyl 2-nitroacetate (10, R1 = H) and the acceptor but-3-en-2-one demonstrated that C. antarctica lipases A and B (CALA and CALB, respectively) give the highest conversions of the substrates. Considerable activity was also found for lipases from Mucor miehei (MML) and porcine pancreas (PPL). Conversions of 99 and 63% have been established by immobilized CALB (2.5% w/w) and CALA (1.6% w/w), respectively. Conversions drop to 16 and 9% in the presence of CALA (1.6% w/w) and CALB (1.6% w/w), respectively, when the sterically more demanding donor methyl 2-nitropropanoate (10, R1 = Me) is used. The chiral products 11 are obtained as racemic mixtures.

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