Asymmetric nucleophilic dearomatization of diazarenes by anion-binding catalysis

Abstract

The first anion-binding organocatalyzed enantioselective Reissert-type dearomatization of diazarenes has been developed. This reaction represents a synthetic challenge since diazarenes have various reactive sites. The use of a chiral tetrakistriazole as a C-H-based hydrogen-donor catalyst allowed the straightforward highly regio- and enantioselective synthesis of a variety of chiral diazaheterocycles.

Anion Templated Supramolecular Structures Assembled using 1,2,3‐Triazole and Triazolium motifs

“…Due to the chirality of the catalyst, only one hand of the helix is observed, giving impressive enantiomeric ratios of up to 98 : 2 in the final product. The same group have subsequently synthesised related chiral foldamers and shown that they can act as enantioselective catalysts for the dearomatization of pyridines, [37] isoquinolines, [38] and diazarenes [39] …”

Synthetic Strategies, Reactivity and Applications of 1,5-Naphthyridines

“…A good regioselectivity of 95:5 was obtained in favor of the C-2-addition product 127 when 2,2,2-trichloroethyl chloroformate (trocCl) was used in the presence of methyl tert -butyl ether (MBTE) ( Scheme 52 ). After the separation from the minor 4-addition product 128 , the 2-addition compound 127 was obtained in 86% yield and a good 83:17 enantiomeric ratio [ 88 ].…”

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

“…Following the aforementioned studies, the Mancheno group designed and synthesized various chiral triazole-based complexes such as L2–L4 (Scheme 2) [36–39]. It was proposed that while these triazole derivatives are conformationally flexible, upon their binding to halogen anions these complexes adopt a reinforced chiral helical conformation.…”

“…Application of chiral triazole-based catalysts L3 and L4 for counterion activation of pyridinium, quinolinium and isoquinolinium salts by Mancheno and co-workers [36–39]. …”