N-Heterocyclic Carbene-Catalyzed Truce–Smiles Rearrangement of N-Arylacrylamides via the Cleavage of Unactivated C(aryl)–N Bonds

Abstract

We report on the N-heterocyclic carbene (NHC)-catalyzed Truce–Smiles rearrangement of aniline derivatives, in which an unactivated C­(aryl)–N bond is cleaved, leading to the formation of a new C­(aryl)–C bond. The key to the success of this reaction is the utilization of a highly nucleophilic NHC, which enables the formation of a highly nucleophilic ylide intermediate that is generated from an α,β-unsaturated amide.

Nickel-catalyzed 1,4-aryl rearrangement of aryl N-benzylimidates via C–O and C–H bond cleavage

“…In this reaction, a 1,4-aryl shift via the cleavage of C–O and C–H bonds occurs, leading to the formation of a new C–C bond (Scheme 1, bottom). 3…”

Reactions of 1-Trifluoromethylprop-2-yne 1-Iminium Salts with Nitroanilines: Synthesis of 4-Trifluoromethylnitroquinolines and 1,2,3-Trisubstituted 5-Trifluoromethylpyrroles

“…In this step, an α,β-unsaturated azomethine ylide intermediate would act as the carbon nucleophile (see Scheme S1 in the Supporting Information). 32 Anyway, the reaction course is different from our recently published, triphenylphosphane promoted synthesis of α-trifluoromethylpyrroles from propyniminium salts 1 , which proceeds via 3-dimethylamino-3-trifluoromethylallenyl phosphonium salts. 23…”

Recent Advances in the Smiles Rearrangement: New Opportunities for Arylation

“…Tobisu and co-workers showed how N-arylacrylamide starting material 37 could be treated with an NHC catalyst (38) to yield rearranged, arylated products (Scheme 9). [39] After formation of the deoxy-Breslow intermediate via Michael addition, a Meisenheimer complex can be formed between the terminal alkenyl carbon of the starting material and the ipso position of the migrating ring, mediating the rearrangement and giving product 39. Subsequent elimination completes the catalytic cycle, returning the active NHC catalyst.…”