Rh(II)-Catalyzed C–N Bond Formation Using Enynones and N–H Imines: An Approach to Diarylmethylamines

Abstract

A Rh(II)-catalyzed furyl carbene N−H insertion reaction involving an N-sp 2 -hybridized imine is described, which represents an atom-economical route by which to access diarylmethylamine derivatives with high efficiency and broad substrate scope. An unusual reaction mechanism is proposed, in which the rhodium catalyst plays a dual role in facilitating enynone cyclization via activation and enhancement of the nucleophilicity of the NH imine.

Accessing Functionalized Furans from Reacting Enynones and Enynals through Furyl Metal Carbenes

“…The Kim group recently developed rhodium(II)‐catalyzed C−N bond formation reactions using enynones 1 and diaryl imines 92 , yielding diarylmethylamine derivatives 93 (Scheme 35). [49] Based on experimental results, NMR, and HR‐MS investigations, a reaction mechanism was proposed. The Rh 2 (OAc) 4 catalyst serves a dual role, facilitating enynone cyclization and enhancing the nucleophilicity of the imine.…”

Synthesis of N-, O-, and S-heterocycles from aryl/alkyl alkynyl aldehydes

“…Recently, an atom-economical approach to the synthesis of furan derivatives starting from aryl alkynyl aldehyde was disclosed by Kim et al ( Scheme 59 ). 72 In the procedure, at first, coordination of rhodium( ii ) with nitrogen atom of diarylimine 43b occurred that enhanced N–H acidity. After the annulation of 43a to form cyclized intermediate B, the authors proposed a nucleophilic addition of Rh( ii )-iminyl complex A into B resulting in target product 43c.…”

DFT study on stereoselective Rh-catalyzed intramolecular [2 + 2 + 2] cycloaddition of allene–ene–ynes

“…10 In the past few decades, many transition metals have been employed to catalyze cycloaddition reactions, such as Rh, Pd, Ru, Ni, Zn, Fe, Ir, Ag, Co, Au, Mn, and so on. 11 Rh transition metal catalysts have been used to catalyze cycloaddition reactions, for example, [4 + 2], 12 [3 + 2], 13 [5 + 1], 14 [2 + 2] 15 and [5 + 2] cycloaddition reactions. 16…”