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Palladium-catalyzed regiodivergent arylamination/aryloxygenation of allenamide†
Yi Yang,Hui Wang,Zehua Sun,Xinjin Li,Fenggang Sun,Qing Liu,Lizhi Zhang,Liping Xu,Hui Liu
Organic Chemistry Frontiers Pub Date : 09/12/2022 00:00:00 , DOI:10.1039/D2QO01271E
Abstract

A palladium-catalyzed multi-component regiodivergent arylamination/aryloxygenation of allenamide is reported. The bases are critical to the chemoselectivity and regioselectivity: (1) Cy2NMe as a base could lead to distal addition that generated a 2,1-arylamination product; (2) Ag2CO3 as a base could result in proximal addition for a 2,3-aryloxygenation product via a four-component transformation, including an unexpected CO2 insertion from Ag2CO3. Notably, the corresponding alkenes formed in 2,3-arylamination could be presented with excellent Z configuration, which was modulated via the steric hindrance of a coordinated palladium intermediate. Two possible π-allyl-Pd complexes were proposed for the resulting regioselectivity: the neutral η3 π-allyl-Pd complex favored the γ substitution where there was less steric hindrance; cationic η1 π-allyl-Pd complex generated via the coordination of Ag favored the reductive elimination at the allylic position adjacent to nitrogen.

Graphical abstract: Palladium-catalyzed regiodivergent arylamination/aryloxygenation of allenamide
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