Green asymmetric synthesis of Warfarin and Coumachlor in pure water catalyzed by quinoline-derived 1,2-diamines

Abstract

A green protocol for water-tolerant iminium-type asymmetric Michael reaction cooperatively catalyzed by 1,2-di(quinoline)ethane-1,2-diamine/mandelic acid was proposed.

Primary Amine Catalyzed Activation of Carbonyl Compounds: A Study on Reaction Pathways and Reactive Intermediates by Mass Spectrometry

“…Chin explored the reaction using catalysts 2 and 3 [15] while we introduced catalyst 4 inspired by the work of Zlotin. [16] In a typical experiment, small amount of ongoing reaction was largely diluted in methanol and introduced by infusion into ESI source to collect spectra producing a series of time points. The reaction mixtures were stirred in THF at room temperature with (10-fold excess) or without acetic acid.…”

“…To extend the ESI‐MS approach also to the other aminocatalysts, we investigated the same reaction catalyzed by chiral vicinal aliphatic diamines 2 – 4 . Chin explored the reaction using catalysts 2 and 3 [15] while we introduced catalyst 4 inspired by the work of Zlotin [16] . In a typical experiment, small amount of ongoing reaction was largely diluted in methanol and introduced by infusion into ESI source to collect spectra producing a series of time points.…”

Сhiral and Racemic Fields Concept for Understanding of the Homochirality Origin, Asymmetric Catalysis, Chiral Superstructure Formation from Achiral Molecules, and B-Z DNA Conformational Transition

“…A similar situation is observed in asymmetric reactions over chiral organocatalysts. A typical example of such reactions is two-component reactions such as aldol reactions of acetone with α-ketoesters, reactions of cyclohexanone derivatives and β-nitrostyrenes (Michael reactions), nitroaldol (Henry) reactions [39,[142][143][144][145][146][147][148], etc. Two plausible transition states TS-R and TS-S ( Figure 13 Figure 14 shows two possible favoured and two disfavoured intermediates which are different from the viewpoint of an approach of the reagents to C2 33 (a front or rear approach).…”

First aromatic amine organocatalysed activation of α,β-unsaturated ketones

“…8 It is important to cite some of these pioneering examples using aliphatic primary chiral amines such as those reported by Chin 9 and Chen 10 or more recently, by Zlotin's group. 11 In contrast, the use of chiral aromatic amines to promote organocatalytic reactions has been eclipsed by the corresponding chiral aliphatic amines, mainly due to the conjugation between the nitrogen lone pair and the aromatic ring. Consequently, this conjugation is responsible for their less nucleophilic behavior in comparison with aliphatic amines.…”