The direct enantioselective synthesis of chiral azaheteroaryl ethylamines from vinyl-substituted N-heterocycles and anilines is reported. A chiral phosphoric acid (CPA) catalyst promotes dearomatizing aza-Michael addition to give a prochiral exocyclic aryl enamine, which undergoes asymmetric protonation upon rearomatization. The reaction accommodates a broad range of N-heterocycles, nucleophiles, and substituents on the prochiral centre, generating the products in high enantioselectivity. DFT studies support a facile nucleophilic addition based on catalyst-induced LUMO lowering, with site-selective, rate-limiting, intramolecular asymmetric proton transfer from the ion-paired prochiral intermediate.
4H-Quinolizin-4-ones are a unique class of heterocycle with valuable physicochemical properties and which are emerging as key pharmacophores for a range of biological targets. A tandem Horner-Wadsworth-Emmons olefination/cyclisation method has been developed to allow facile access to substituted 4H-quinolizin-4-ones encoded with a range of functional groups.
Formal homologation of sp(2)-hybridized boronic acids is achieved via cross-coupling of boronic acids with conjunctive haloaryl BMIDA components in the presence of a suitably balanced basic phase. The utility of this approach to provide a platform for diversity-oriented synthesis in discovery medicinal chemistry is demonstrated in the context of the synthesis of a series of analogues of a BET bromodomain inhibitor.
The direct enantioselective synthesis of chiral azaheteroaryl ethylamines from vinyl‐substituted N‐heterocycles and anilines is reported. A chiral phosphoric acid (CPA) catalyst promotes dearomatizing aza‐Michael addition to give a prochiral exocyclic aryl enamine, which undergoes asymmetric protonation upon rearomatization. The reaction accommodates a broad range of N‐heterocycles, nucleophiles, and substituents on the prochiral centre, generating the products in high enantioselectivity. DFT studies support a facile nucleophilic addition based on catalyst‐induced LUMO lowering, with site‐selective, rate‐limiting, intramolecular asymmetric proton transfer from the ion‐paired prochiral intermediate.
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