Organocatalytic Asymmetric Michael Addition Of Anthrone, α-Aryl Isocyanoesters To Enones

Bifunctional organocatalysts from cinchona alkaloid was developed for the asymmetric Michael addition of anthrone to enones. It was envisaged that the bridgehead nitrogen in organocatalyst would activate the anthrone while the thiourea moiety would simultaneously activate and organize the enones through hydrogen bonding interactions, and control the enantioselectivity of the desired product through the three dimensional spatial arrangement of the organocatalyst bearing tertiary amine and thiourea. Under the optimized reaction conditions, a variety of enones reacted with anthrone smoothly affording the product in good yields (up to 97%) and excellent ee values (up to 93%). It developed a new method of asymmetric catalysis Michael addtion of anthrone toα,β-unsaturated ketones.Asymmetric Michael additon of a-aryl isocyanoesters to enones was catalyzed through iminium mechanism by organocatalyst develped from the naurtal amino acids, which are nontoxic, inexpensive and readily available. The asymmetric reaction provided a new method to access quaternary chiral carbon certer compounds. Under the optimal reaction conditions, the enones reacted with methyl 2-isocyano-2-phenylacetate affording the products in good yields and moderate enantioselectivities. Our work affords the useful suggestion for the posterior research.