Copper‐Catalyzed Rearrangement of N‐Aryl Nitrones into Epoxyketimines

Copper‐Catalyzed Carbonyl Group Controlled Coupling of Isatin Oximes with Arylboronic Acids To Prepare N‐Aryloxindole Nitrones

“…of Cu(OAc) 2 to give the desired products 3aq – 3as in 73, 14, and 60 % yield, respectively. It is worth noting that the preparation of ortho ‐substituted aryl and heteroaryl nitrones were not reported in Anderson's work However, none of the desired product 3at was observed, even by using 1.0 or 2.0 equiv. of Cu(OAc) 2 in the reaction.…”

“…Although Anderson's work did not report the details of ( E )/( Z ) mixtures of N ‐arylchalcone nitrone 3sa , we did proceed to employ oxime 1s under our coupling conditions (Scheme ). When oxime 1s [( E )/( Z ) mixture, 3:1] was used in the reaction under the optimized conditions, nitrone 3sa was obtained in only 46 % yield with a 5:1 ( E )/( Z ) ratio [Scheme , Equation (1)].…”

“…( E )‐ N ‐[( E )‐1,3‐Diphenylallylidene]aniline Oxide (3sa): Yellow solid (0.023 g, 38 % yield). 1 H NMR (400 MHz, CDCl 3 ): δ = 8.20 (d, J = 16.4 Hz, 1 H), 7.54 (d, J = 7.2 Hz, 2 H), 7.36–7.26 (m, 8 H), 7.22–7.17 (m, 5 H), 6.73 (d, J = 16.4 Hz, 1 H) ppm.…”

“…Although oximes can serve as ambient nucleophiles (N‐ or O‐nucleophile), most examples of coupling by transition‐metal catalysis provide O ‐arylation products . In 2013, Anderson's group pioneered a strategy for the preparation of N ‐arylnitrones from a copper‐promoted cross‐coupling reaction between oximes and arylboronic acids under mild conditions (Scheme C) . This method is superior for the synthesis of N ‐arylnitrones and was further employed by this group for the preparation of N ‐vinylnitrones.…”

Solvent‐Controlled Bifurcated Cascade Process for the Selective Preparation of Dihydrocarbazoles or Dihydropyridoindoles

“…[1] Cascade reactions are important and proficient transformations that rapidly build molecular complexity and have been employed for the synthesis of complex molecules in both target-and diversity-oriented syntheses. [5] To our delight, we discovered that either dihydrocarbazoles 1 or dihydropyridoindoles 2 can be formed as the sole products of the reaction of N-aryl-a,b-unsaturated nitrones 3 with electron-deficient allenes 4 depending on the choice of solvent (Scheme 1). [5] To our delight, we discovered that either dihydrocarbazoles 1 or dihydropyridoindoles 2 can be formed as the sole products of the reaction of N-aryl-a,b-unsaturated nitrones 3 with electron-deficient allenes 4 depending on the choice of solvent (Scheme 1).…”