Rhodium(II)-catalyzed reactions of 3-diazo-2,4-chromenediones. First one-step synthesis of pterophyllin 2

Versatile approach for the synthesis of furo-coumarin derivatives

Abstract:

Owing to useful physio-chemical properties of furo-coumarin derivatives, their synthetic and mechanistic investigation has been reported here. We have demonstrated a range of synthetic approach to access furan-fused coumarin derivatives. Many metal mediated, base and acid catalyzed approach have been revealed for the construction of thiscoumarin based fused heterocycles of biological importance. In addition to this, microwave assisted synthetic routes have been also revealed. The last and useful approach for the synthesis of these heterocycles includes use of purely solvent as a reaction media for synthesizing these interesting classes of heterocycles.

Synthetic Routes to Coumarin(Benzopyrone)-Fused Five-Membered Aromatic Heterocycles Built on the α-Pyrone Moiety. Part II: Five-Membered Aromatic Rings with Multi Heteroatoms

Coumarins are natural heterocycles that widely contribute to the design of various biologically active compounds. Fusing different aromatic heterocycles with coumarin at its 3,4-position is one of the interesting approaches to generating novel molecules with various biological activities. During our continuing interest in assembling information about fused five-membered aromatic heterocycles, and after having presented mono-hetero-atomic five-membered aromatic heterocycles in Part I. The current review Part II is intended to present an overview of the different synthetic routes to coumarin (benzopyrone)-fused five-membered aromatic heterocycles with multi-heteroatoms built on the pyrone ring, covering the literature from 1945 to 2021.

Furo[3,2-c]coumarins carrying carbon substituents at C-2 and/or C-3. Isolation, biological activity, synthesis and reaction mechanisms

The isolation, biological activity and synthesis of natural furo[3,2-c]coumarins are presented, covering mainly the developments in the last 35 years. The most relevant approaches toward the synthesis of 2-substituted, 3-substituted and 2,3-disubstituted heterocycles are also discussed, with emphasis on the efficiency of the processes and their mechanisms.

Copper-catalyzed (4+1) and (3+2) cyclizations of iodonium ylides with alkynes

The copper(ii)-catalyzed (4+1) cyclizations and copper(i)-catalyzed (3+2) cycloadditions of iodonium ylides and alkynes have been successfully developed. The corresponding highly functionalized heterocyclic products were prepared conveniently.

Total syntheses of gerberinol I and the pterophyllins 2 and 4 using the Casnati–Skattebøl reaction under different conditions

The total syntheses of the title compounds were achieved from a single coumarin precursor, taking advantage of the temperature-dependent divergent outcomes of the Casnati–Skattebøl reaction.

Theophylline as the catalyst for the diastereoselective synthesis of trans-1,2-dihydrobenzo[a]furo[2,3-c]phenazines in water

Theophylline-catalyzed efficient and environmentally benign procedure for the diastereoselective synthesis of trans-1,2-dihydrobenzo[a]furo[2,3-c]phenazines with pyridinium ylide assisted domino reaction in water.

Novel one-pot synthesis of diverse γ,δ-unsaturated β-ketoesters by thermal cascade reactions of diazodicarbonyl compounds and enol ethers: transformation into substituted 3,5-diketoesters

Novel and efficient synthesis of diverse γ,δ-unsaturated β-ketoesters was accomplished by thermal cascade reactions of diazodicarbonyl compounds with enol ethers and the synthesized compounds were further transformed into the corresponding 3,5-diketoesters.

Potassium Thiocyanate as an Efficient Catalyst in One-Pot Reaction of Dialkyl Acetylenedicarboxylates with Indane-1,3-Dione

The potassium thiocyanate-catalysed reaction of dialkyl acetylenedicarboxylates with indane-1,3-dione in acetone, led to dialkyl 4-oxo-3,4-dihydro-2 H-indeno[1,2- b]furan-2,3-dicarboxylates in good yields. The presented one-pot method is simple and effective with mild conditions.

Novel synthesis of substituted furo[3,2-c]chromen-4-ones via four-component reaction from substituted nitrostyrenes, aromatic aldehydes, coumarins, and ammonium acetate

An efficient and direct synthesis of 2-arylideneamino-3-aryl-4H-furo[3,2-c]chromen-4-ones has been developed via four-component reaction from substituted nitrostyrenes, aromatic aldehydes, coumarins, and ammonium acetate under very mild conditions, which involves sequentially a Michael addition, an aza-nucleophilic addition, of the imine to the double bond, an intermolecular nucleophilic addition and a dehydration reaction. The resulting biologically intriguing structures could have broad applications in related biomedical-program structures.

Selective syntheses of Δ(α,β) and Δ(β,γ) butenolides from allylic cyclopropenecarboxylates via tandem ring expansion/[3,3]-sigmatropic rearrangements

Allylic cyclopropenecarboxylates undergo ring expansion reactions to give 2-allyloxyfuran intermediates, which subsequently rearrange to Δ(β,γ) butenolides via a Claisen rearrangement or to the corresponding Δ(α,β) butenolides via further Cope rearrangement. Also described are methods for chirality transfer in the rearrangement of nonracemic allylic esters.

One-pot synthesis of furocoumarins via sequential Pd/Cu-catalyzed alkynylation and intramolecular hydroalkoxylation

A novel and rapid assembly of an interesting class of furocoumarins-4H-furo[3,2-c]chromen-4-ones has been successfully achieved using one-pot sequential coupling/cyclization strategy with easily available starting materials 3-bromo-4-acetoxycoumarins and terminal alkynes. The key synthesis involves Pd/Cu-catalyzed alkynylation with in situ prepared dialkynylzincs followed by intramolecular hydroalkoxylation.

An efficient approach to dihydrofurocoumarins via palladium-catalyzed annulation of 1,3-dienes by o-iodoacetoxycoumarins

The palladium-catalyzed annulation of 1,3-dienes by o-iodoacetoxycoumarins provides an efficient method for the synthesis of biologically interesting dihydrofurocoumarins. The presence of the acetyl group on the phenolic oxygen and the use of silver carbonate as a base are crucial for this process. This reaction is very general and regio- and stereoselective, and a wide variety of terminal, cyclic, and internal 1,3-dienes can be utilized. Derivatization of the annulation products provides an efficient approach to numerous analogues of natural products.