A novel and expedient cascade strategy has been demonstrated for the synthesis of fused benzo‐aza‐oxa‐[5‐6‐5] tetracycles in high yields and diastereoselectivities (up to 20 : 1 dr). The strategy was fulfilled through palladium‐catalyzed oxidative convergent assembly of functionally divergent anilines and 3‐butenoic acid with five chemical bonds constructed. Coupled with control experiments and deuterium labelled studies, DFT calculations were performed for the proposed mechanism. The utility of the illustrated strategy is emphasized by gram‐scale syntheses, late‐stage functionalization, and the transformation to a key core of natural products such as martinellic acid and seneciobipyrrolidine.
Catalytic 1,1-difunctionalization of unactivated alkenes with two nucleophiles has attracted a great deal of interest but remains a challenge in synthetic chemistry. Here, palladium-(II)-catalyzed Nu/Nu′-type 1,1-oxamidation and 1,1-diamination of unactivated alkenyl carbonyl compounds followed by amination are described. The distinguishing features of this reaction include the lack of a directing group, good functional group tolerance, and easily operational catalytic reaction conditions. Mechanistic investigations support a unique route involving two consecutive nucleopalladations for this 1,1-difunctionalization.
Although the synthesis of amino lactones with various nitrogen sources has achieved great success, variants focused on aromatic amine counterparts still remain elusive. Herein, we communicate the intermolecular oxyamination reaction of aromatic amines and unactivated alkenyl carbonyl compounds under palladium catalysis. In the reaction, both primary and second aromatic amines yield the corresponding β-arylamino-γ-lactones efficiently. A key step in this process involves a Pd II /Pd IV catalytic cycle incorporating a 1,2-(C−N)/(C−O) dyotropic rearrangement. This reaction demonstrates mild reaction conditions and good functional group compatibility.
A novel and expedient cascade strategy has been demonstrated for the synthesis of fused benzo-azaoxa- [5-6-5] tetracycles in high yields and diastereoselectivities (up to 20 : 1 dr). The strategy was fulfilled through palladium-catalyzed oxidative convergent assembly of functionally divergent anilines and 3-butenoic acid with five chemical bonds constructed. Coupled with control experiments and deuterium labelled studies, DFT calculations were performed for the proposed mechanism. The utility of the illustrated strategy is emphasized by gram-scale syntheses, late-stage functionalization, and the transformation to a key core of natural products such as martinellic acid and seneciobipyrrolidine.
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