The Use of a Rhodium Catalyst/8-Aminoquinoline Directing Group in the C-H Alkylation of Aromatic Amides with Alkenes: Possible Generation of a Carbene Intermediate from an Alkene

Abstract

Rhodium-catalyzed alkylation reactions of C-H bonds (hydroarylation) in aromatic amides that contain an 8-aminoquinoline as a directing group with alkenes are discussed. Various alkenes, including acrylic esters, styrenes, α,β-unsaturated butyrolactones, dihydrofurans, maleimides, and norbornene derivatives are applicable to this C-H alkylation. The reaction with norbornene gives unusual endo-hydroarylation products in a high degree of selectivity. The use of a carboxylic acid as an additive dramatically increases both the reactivity and the selectivity of the reaction. The results of deuteriumlabeling experiments suggest that hydrometalation or carbometalation, which are commonly accepted mechanisms for C-H alkylation reactions, are not involved. Instead, the reaction appears to proceed through a rhodium carbene intermediate generated from the alkene.

Cobalt(II)-Catalyzed Acyloxylation of C–H Bonds in Aromatic Amides with Carboxylic Acids

“…New types of chelation systems have been developed that now permit the characteristic functionalization of C–H bonds. One such example involves the use of an N,N′ -bidentate chelation system . Although noble metals, such as Pd, Rh, Ir, Pt, and Ru, are typically used as catalysts in chelation-assisted C–H functionalization, the use of first-row transition metals, such as Fe, Co, Ni, and Cu, has also received much interest because these metals are earth abundant and therefore less expensive than noble metals.…”

Rhodium‐Catalyzed C(sp2)‐ or C(sp3)−H Bond Functionalization Assisted by Removable Directing Groups

“…Bidentate Amide Directing Groups CÀHb ond activation assisted by ab identate directing group is awell-established procedure for the functionalization of amides because of its strong coordination ability towards am etal center.O ne of the most versatile and reliable bidentate directing groups developed to date is the 8-aminoquinoline amide moiety,w hich was introduced by Daugulis and co-workers in 2005 for use in Pd-catalyzed CÀHarylation reactions. [187][188][189][190][191][192][193] In 2014, the Rh I -catalyzed alkylation of 8-aminoquinoline amides was first reported in the reaction of a,b-unsaturated esters (Scheme 53 a). [173][174][175][176][177][178][179][180][181][182][183][184][185][186] Theu tility of an 8aminoquinoline moiety for the Rh-catalyzed functionalization of amides discussed here was mainly reported by Chatani and co-workers in terms of various alkylation and alkenylation reactions.…”

“…[173][174][175][176][177][178][179][180][181][182][183][184][185][186] Theu tility of an 8aminoquinoline moiety for the Rh-catalyzed functionalization of amides discussed here was mainly reported by Chatani and co-workers in terms of various alkylation and alkenylation reactions. [187][188][189][190][191][192][193] In 2014, the Rh I -catalyzed alkylation of 8-aminoquinoline amides was first reported in the reaction of a,b-unsaturated esters (Scheme 53 a). [187] Av ariety of a,bunsaturated esters can be used in this reaction, with the desired products being produced in good to excellent yields.…”

A Synthesis of 3,4-Dihydroisoquinolin-1(2H)-one via the Rhodium-Catalyzed Alkylation of Aromatic Amides with N-Vinylphthalimide

“…Yorimistu recently reported the Ir­(I)-catalyzed hydroalkylation of α-C–H bonds in urea derivatives . We herein report on the rhodium-catalyzed alkylation of aromatic amides − with N -vinylphthalimide, in which a 2-aminoethyl moiety is introduced at the ortho -position in an aromatic amide. In addition, a further conversion of the products to 3,4-dihydroisoquinolin-1­(2H)-one derivatives via a one-pot reaction is reported (Scheme ).…”

“…A high ratio of H/D exchange occurred at the ortho position (0.7 H), and the Two mechanisms are illustrated in Scheme 4 (catalytic cycle A and B), based on the results obtained in the above deuterium-labeling experiments and our previously reported studies. 23 The coordination of the quinoline nitrogen in the aromatic amide 1 followed by the oxidative addition of an N− H bond gives the Rh(III) complex A. 37,38 The insertion of Nvinylphthalimide into the H−Rh bond in A gives complex B, which affords the rhodium carbene complex C after the elimination of HX.…”