A copper-catalyzed 8-amide chelation-induced remote C-H amination of quinolines has been developed. This direct amination with readily available azodicarboxylates proceeded with perfect C5-regioselectivity offering amino-substituted 8-aminoquinolines, important bioactive molecular scaffolds, in very high yields (up to 96%). A single-electron transfer (SET)-mediated mechanism with kH /kD =1.1 was proposed after trapping of the radical intermediate.
An amination reaction of in situ generated gem-difluoro-enolates has been explored with electrophilic nitrogen sources. While their exposure to azodicarboxylates smoothly produced fluorinated α-amino ketones, reaction with nitrosoarenes (nitroso aldol reaction) furnished α-ketoamides in very high yields (up to 94%). The reaction is very fast (typically completed within 5 min) and scalable and tolerates various sensitive functional groups. Synthetic utility of this process was highlighted through the production of diverse nitrogen heterocycles and an orexin receptor antagonist.
An unprecedented Henry reaction of in situ generated nitrosocarbonyl intermediates and concomitant denitration cascade has been developed. The reaction is catalyzed by organic base at room temperature offering α-ketoamides, a demanding scaffold for drug discovery, in high yields. An alteration of substitution pattern also produced α-keto oximes, a high-value synthon. The protocol features operational simplicity and broad substrate scope.
An efficient organocatalyzed annulation cascade has been established for the stereoselective functionalization of dibenzoxazepine and dibenzothiazepine scaffolds. The protocol used ready‐stock proline as a catalyst and a variety biologically important oxa/thiazepine based polycyclic frameworks featuring congested chiral vicinal tertiary centers were obtained in high yields and excellent diastereoselectivities (>20:1 dr) and enantioselectivities (>96:4 er). Synthetic utility was showcased through the gram‐scale reaction and diverse derivatization sequences.
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