An Efficient Organocatalytic Method for Highly Enantioselective Michael Addition of Malonates to Enones Catalyzed by Readily Accessible Primary Amine-Thiourea
作者:Krzysztof Dudziński、Anna M. Pakulska、Piotr Kwiatkowski
DOI:10.1021/ol3019055
日期:2012.8.17
A practical and highlyenantioselectiveMichaeladdition of malonates to enones catalyzed by simple and readily available bifunctional primary amine-thiourea derived from 1,2-diaminocyclohexane is reported. The addition of weak acids and elevated temperature (ca. 50 °C) improved the efficiency of the Michael reaction. This approach enables the efficient synthesis of 1,5-ketoesters with good yields
-amino acid into L-Leu-based heptapeptides preferentially induced right-handed (P) helical structures. Using 5∼20 mol % of a single helical foldamers-catalyst, enantioselective 1,4-addition reactions of dialkyl malonates to cycloalk-2-enones (5∼7 rings) proceeded to give chiral 3-substituted cycloalkanones with 94∼99% ee in moderate chemical yields, regardless of the ring size of substrates.
Enzyme-Promoted Direct Asymmetric Michael Reaction by Using Protease from Streptomyces griseus
作者:Ling-Ling Wu、Ling-Po Li、Yang Xiang、Zhi Guan、Yan-Hong He
DOI:10.1007/s10562-017-2095-4
日期:2017.8
AbstractThe directasymmetric Michael addition of malonates and enones was promoted by protease from Streptomyces griseus for the first time. Yields of up to 84% with enantioselectivities of up to 98% enantiomeric excess (ee) were achieved under optimized conditions.Graphical AbstractProtease from Streptomyces griseus (SGP) was used for the first time as a biocatalyst in asymmetric Michael reaction of malonates
was suitable for bulkier substrates (sterictuning of the catalyst). Using the La-NMe-linked-BINOL complex, the Michaelreaction of methyl acetoacetate (8a) to 2-cyclohexen-1-one (7b) gave the corresponding Michael adduct 9ba in 82% yield and 92% ee. The linker heteroatom in linked-BINOL is crucial for achieving high reactivity and selectivity in the Michaelreaction of beta-keto esters. The amine moiety