Chemo-, Regio-, and Stereoselective Construction of Core Skeleton of Furo[2,3-b]pyrrole via Multicomponent Bicyclization Reaction

Abstract

An efficient and straightforward N-ethyldiisopropylamine (DIPEA)-catalyzed multicomponent bicyclization reaction was developed to synthesize furo[2,3-b]pyrrole derivatives from β-ketothioamides, glyoxals, and ethyl cyanacetate in EtOH at rt for 1.5 h. This was achieved via a sequential Knoevenagel condensation, Michael addition, and double cyclization, resulting in continuous formation of four chemical bonds (two C-C, two C-O, and one C-N bonds), two five-membered cycles, and three stereogenic centers in a one-pot operation.

Visible-Light-Mediated Synthesis of 1,2,4-Dithiazolidines from β-Ketothioamides through a Hydrogen-Atom-Transfer Photocatalytic Approach of Eosin Y

“…One such simple substrate is β-ketothioamide that has been well-documented as an intriguing synthon because of its exceptional reactivity . β-Ketothioamides are comprehensively exploited to access valuable heterocyclic scaffolds . Furthermore, they not only behave as ambiphilic species (having both nucleophilic and electrophilic characters) but also could be transformed into radical intermediates for further manipulations.…”

“…For the success of any protocol, particularly, the selection of substrate is highly crucial and a governing factor. One such simple substrate is β-ketothioamide that has been well-documented as an intriguing synthon because of its exceptional reactivity . β-Ketothioamides are comprehensively exploited to access valuable heterocyclic scaffolds .…”

NEt3-Promoted Construction of Functionalized 4H-Chromenes via [4+2] Cycloaddition Reaction of ortho-Quinone Methides with β-Ketothioamides

“…Recently β-ketothioamides (KTAs) [13] have received much attention as multifunctional building blocks in organic synthesis and have been extensively used in various carbon-carbon and carbon-heteroatom bond-forming reactions for the construction of heterocycles (Scheme 1, modes A～D [14][15][16][17] ). Although significant progress has been made in this field, the discovery of novel reaction should be an interesting project.…”

Multicomponent Tether Catalysis Synthesis of Highly Functionalized 4-(Pyridin-2-ylmethyl)-2-aminopyrroles via Cascade Reaction Is Accompanied by Decarboxylation

“…Examples are the central cannabinoid receptor antagonist (Figure , URB447), the antitumor agent neolamellarin A, and the antihyperlipidemic agent atorvastatin . Consequently, a greater number of chemists and pharmacologists have been interested in these types of heterocycles and have constructed many protocols for the synthesis of pyrrole derivatives. , A general method involves the use of Paal–Knorr condensations to synthesize pyrroles . Furthermore, N -sulfonyl-1,2,3-triazoles also have been widely used as the substrate to synthesize pyrroles …”