Construction of Benzene Rings by Copper-Catalyzed Cycloaddition Reactions of Oximes and Maleimides: An Access to Fused Phthalimides

Abstract

A useful Cu-catalyzed cycloaddition protocol for the construction of benzene rings has been achieved. The reactions, utilizing readily available oximes and maleimides as starting materials, proceed under mild reaction conditions to generate a series of structurally interesting fused-phthalimides that are difficult to be prepared by conventional methods.

Iron‐Catalyzed, Iminyl Radical‐Triggered Cascade 1,5‐Hydrogen Atom Transfer/(5+2) or (5+1) Annulation: Oxime as a Five‐Atom Assembling Unit

“…A further improvement was achieved by using 1equiv of sodium pivalate as an additive (82 %, entry 14). Considering the influence of the oxime group on the transformation, several O-substituted oximes were studied (entries [15][16][17];however, all the reactions produced the target product in moderate yields.Acontrol experiment demonstrated that catalytic amount of FeCl 2 was indispensable,b ecause 3a cannot be observed in its absence (entry 18). Thus,the optimal reaction conditions were concluded to be the following:F eCl 2 (10 mol %) as the catalyst, PivONa (1 equiv) as the additive, and 1,4-dioxane as the solvent at 100 8 8Cf or 12 h.…”

“…[15] Among the reported approaches toward these compounds,( 5 + +2) annulation reactions are particularly fascinating, because alkenes and alkynes,s tructurally diverse and readily available compounds, could serve as two-atom units in the transformations.N onetheless,most of the known (5+ +2) annulation reactions toward the seven-membered N-heterocycles require the utilization of structurally specific substrates,s uch as vinylaziridines,p yridinium zwitterions,a nd oxiranes,w hich would result in limited molecular diversity. [16] Motivated by the aforementioned work related to the iminyl radical-triggered 1,5-HAT [13,14] and our ongoing research on NÀOb ond transformations toward the N-heterocycles, [17] we envisaged to develop an ew approach involving the iminyl radical-triggered cascade 1,5-HAT/(5+ +2) annulation for the synthesis of the seven-membered N-heterocyclic rings,inwhich the oxime serves as af ive-atom unit. To our best knowledge,s uch aprotocol remains unexplored.…”

Recent Advances in Copper-Catalyzed N-O Cleavage Strategy

“…48c, 32% 48d, 86% 2018 年, 魏晔课题组 [27] 报道了碘化亚铜催化马来 2018 年, 江焕峰课题组 [32] 发展了碘化亚铜催化链 2018 年, 严汝龙课题组 [33] 2018 年, 郭丽娜课题组 [34] 报道了氧化亚铜催化 α,β-…”

Redox-Active Heteroacene Chromophores Derived from a Non-Linear Aromatic Diimide

“…More recently, Yang et al. reported 31 the elegant Cu-catalyzed cycloaddition of two equivalents of maleimide with oximes to generate the MDI core. This method and other cycloaddition approaches, 32,33 however, are limited in substrate scope and are not suitable for producing halogenated MDIs.…”