Rhodium-Catalyzed Selective Mono- and Diamination of Arenes with Single Directing Site “On Water”

Abstract

A Rh(III)-catalyzed selective C-H amination of 2-phenylpyridine derivatives is reported. With pyridine as a directing group, the reaction has high mono- or diamination selectivity, and a wide range of effective substrates, including electron-deficient and -rich aryl azides. Water helps to promote C-H activation, and the concept of a water promoted rollover mechanism is postulated for the diamination step. The reactions were conducted using a Schlenk flask and proceeded smoothly "on water" under atmospheric conditions with nitrogen gas as the only byproduct.

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

“…For example, Lu demonstrated the reaction of 2-phenylpyridines with aryl azides in water, also allowing for a double ortho -functionalisation with two different azides ( Scheme 125A ). 757 The use of anthranils (2,1-benzisoxazoles) as alternative, more stable nitrene precursors was independently reported by Wang and Li. 758 , 759 The reaction of indoles with anthranils using polar protic solvents (H 2 O or MeOH) and Rh catalysis resulted in a tandem amination–cyclisation process, leading to the formation of indoloquinolines ( Scheme 125C ).…”

Organic synthesis reactions on-water at the organic–liquid water interface

“…Lu and co-workers examined the rhodium(III) catalysed C-H monoamination of arenes using on-water conditions. 60 substituted nitrones 100 using a chiral copper-diamine complex under base catalysed conditions. 62 The combination of Cu(OTf)2 and the chiral diamine ligand with the nBu2NH in water generated a blue precipitate.…”

Recent Advances and Prospects of Organic Reactions “On Water”

“…Water promoted C−H amination of 2‐phenylpyridine derivatives catalysed by Rh(III) salt was reported by Lu and co‐workers . Use of 4 mol % of [RhCp*Cl 2 ] 2 along with 4 mol% of NaBARF [sodium tetrakis(3,5‐bis(trifluoromethyl)phenyl)borate) at 110 °C was the optimal reaction condition (Scheme ).…”