Induction of axially chiral N–C bonds in N-aryl acridane and related complexes by chromium tricarbonyl migration reactions

Abstract

The thermal chromium tricarbonyl migration reaction induced axially chiral N-C bonds of N-aryl acridane and related complexes in good yield with outstanding enantiomeric excess.

Advances in Stereoconvergent Catalysis from 2005 to 2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

“…Replacing the tert -butyl group on ring B with the smaller isopropyl or phenyl groups was detrimental to the observed enantioselectivities. 220,221,222 …”

“…Thus, for R = H, the indole product was obtained in 60% ee, whereas for R = Br, the ee was determined to be 83%, correlating agreeably with the hypothesis. Replacing the tert -butyl group on ring B with the smaller isopropyl or phenyl groups was detrimental to the observed enantioselectivities. − …”

A general route for synthesis of N-aryl phenoxazines via copper(i)-catalyzed N-, N-, and O-arylations of 2-aminophenols

“…It was clearly revealed that the conversion of 4a into 7 was the ratedetermining step and the conversion of 7 into 8 was a fast process. As shown in Scheme 3, this hypothesis was proved by using the pre-made 7 as a substrate to give 8 in 88% yield within 4 h. This result also strongly indicated that the unsymmetric triphenylamine 2-[N-(2-halophenyl)-N-phenylamino]phenol (6) may be synthesized easily via Cu(I)-catalyzed N-arylation between iodobenzene (3a) and 2-[N-(2-halophenyl)amino]phenol (5). Thus, we may expect that N-phenyl phenoxazine (2a) is synthesized via Cu(I)-catalyzed intramolecular O-arylation of 6.…”

“…As shown in Scheme 1, we report herein a novel Cu(I)-catalyzed tandem reaction for N-and O-arylations of 2-[N-(2-halophenyl)amino]phenols (5), by which a series of the derivatives of 2 were prepared efficiently in one-ask. Since the precursor 5 was prepared also by Cu(I)-catalyzed N-arylation of 2-aminophenols…”

Synthesis of Axially Chiral C–N Scaffolds via Asymmetric Coupling with Enantiopure Sulfinyl Iodanes

“…Following such a challenging goal, Jørgensen developed the organocatalytic amination of 2-naphthols with azadicarboxylates, and Kamikawa and Uemura reported diastereoselective S N Ar reactions between planar chiral arene chromium complexes and indoles (Scheme ). In clear contrast, although transition-metal-catalyzed C–N couplings such as the Ullmann reaction or Buchwald–Hartwig transformations have established themselves as benchmark approaches to create C–N linkages, no asymmetric version of these reactions has been reported. The major difficulty in accessing atropisomerically pure molecules via C–N cross-couplings arises from the clear antagonism between the generally harsh reaction conditions required for these types of hindered couplings and the low atropostability of the C–N bonds (Scheme ).…”