Quinone-catalyzed oxidative deformylation: synthesis of imines from amino alcohols

Abstract

A new method for imine synthesis by way of quinone-catalyzed oxidative deformylation of 1,2-amino alcohols is reported. A wide range of readily accessible amino alcohols and primary amines can be reacted to provide N-protected imine products. The methodology presented provides a novel organocatalytic approach for imine synthesis and demonstrates the synthetic versatility of quinone-catalyzed oxidative C–C bond cleavage.

Preparation of Enantiomerically Pure β,β‐Diaryl β‐Hydroxy‐α‐Amino Acids and Evaluation of Their Potential as Organocatalysts

“…We initially attempted Jones oxidation of β‐aminodiol 3 d following the same method as that used for compound 3 a ; however, as mentioned above, we confirmed that the reaction led only to decomposition of 3 d , and none of the target carboxylic acid 4 d was observed. Furthermore, careful examination of the reaction mixture disclosed formation of the corresponding benzophenone, probably through oxidative carbon−carbon cleavage in a similar fashion to that of 1,2‐aminoalcohols . This decomposition could not be suppressed when using metallic oxidants such as PDC, PCC, MnO 2 , and cat .…”

“…Furthermore, careful examination of the reaction mixture disclosed formation of the corresponding benzophenone, probably through oxidative carbonÀ carbon cleavage in a similar fashion to that of 1,2aminoalcohols. [32][33][34] This decomposition could not be suppressed when using metallic oxidants such as PDC, PCC, MnO 2 , and cat. RuCl 3 /NaIO 4 .…”

Modular synthesis of pyrrole-fused heterocycles via glucose-mediated nitro-reductive cyclization

“…In the subsequent step, 2-pyrrolyl aniline III could undergo a condensation reaction with the preformed HCHO, which was generated from DMSO at a high temperature under acidic conditions, 28 resulting in the formation of imine VII . 29 The intramolecular Michael addition with imine VI could lead to the production of VIII via re-aromatization of the intermediate VII . Furthermore, aerobic oxidation of VIII could produce product 3a .…”

Exploiting Iminoquinones as Electrophilic at Nitrogen “N+” Synthons for C–N Bond Construction

“…Our research group has developed several quinone-catalyzed or quinone-mediated transformations for the synthesis of amine derivatives. During the development of a stepwise umpolung approach for the α-allylation of benzylic amines with allylpalladium species, we observed that iminoquinones derived from 3-butenylamines underwent cyclization by intramolecular C–N bond formation, leading to pyrrole products in low yields (see the Supporting Information).…”