Synthesis and Reactivity of Electron-Deficient 3-Vinylchromones

Abstract

The literature data on the methods of synthesis and reactivity of electron-deficient 3-vinylchromones containing electron-withdrawing groups at the exo-cyclic double bond are summarized and systematized for the first time. The main methods for obtaining these compounds are Knoevenagel condensation, Wittig reaction, and palladium-catalyzed cross-couplings. The most important chemical properties are transformations under the action of mono- and dinucleophiles, ambiphilic cyclizations, and cycloaddition reactions. The cross-conjugated and polyelectrophilic dienone system in 3-vinylchromones provides their high reactivity and makes these compounds valuable building blocks for the preparation of more complex heterocyclic systems. Chemical transformations of 3-vinylchromones usually begin with an attack of the C-2 atom and are accompanied by the opening of the pyrone ring followed by recyclization, in which the carbonyl group of chromone, an exo-double bond or a substituent at it can take part. The mechanisms of the reactions are discussed, the conditions for their implementation and the yields of the resulting products are indicated. This review focuses on an analysis and generalization of the knowledge that has accumulated on the chemistry of electron-deficient 3-vinylchromones, mostly over the past 15 years.

Fluorescent 5H‐Pyrano[3,2‐c]chromenes: Synthesis, Photophysical Properties and Sensing of Nucleophilic Anions

“…Based on earlier studies, [12][13][14] we proposed that this reaction begins with a nucleophilic attack of the ester (5) at position 2 of the chromone 1 a. This is accompanied by the opening of the γpyrone system.…”

Theoretical Investigations on the Rh(III)-Catalyzed Oxidative C–H Activation/Annulation of Salicylaldehydes with Masked Enynes: Mechanism Insights and Regioselectivity Origins

“…Chromones are a significant class of oxygen-containing heterocycles that are present in natural products and pharmaceuticals, exhibiting noteworthy biological activities such as anti-inflammatory, antimicrobial, antioxidant, and anticarcinogenic properties. , The synthesis of chromones can be accomplished through transition-metal-catalyzed sequential C–H activation/annulation of salicylaldehydes with suitable coupling partners. − Despite these advanced methods for constructing new skeleton molecules, there is still an urgent need to synthesize new related molecules, such as 3-vinyl chromone, which is found in many bioactive compounds and has antioxidant, antiproliferative, and PDE10 inhibitory activities, − and therefore remains of very important value in organic synthesis.…”

“… 1 , 2 The synthesis of chromones can be accomplished through transition-metal-catalyzed sequential C–H activation/annulation of salicylaldehydes with suitable coupling partners. 3 − 7 Despite these advanced methods for constructing new skeleton molecules, there is still an urgent need to synthesize new related molecules, such as 3-vinyl chromone, 8 which is found in many bioactive compounds and has antioxidant, antiproliferative, and PDE10 inhibitory activities, 9 − 11 and therefore remains of very important value in organic synthesis.…”

Tandem Ring‐Opening/Double Ring‐Closing Synthesis of 1,2,4‐Triazolo[1,5‐a]pyridines from Chromone‐Containing Acrylonitriles

“…3‐Vinylchromones 1 are more convenient and versatile in such syntheses. These structures have several electrophilic centers that differ greatly in reactivity, which ensures high selectivity of tandem processes [4b] . Based on the ANRORC reaction of chromones 1 with 1,3‐binucleophiles or 1,2‐amphiphiles, methods for the synthesis of a number of complex heterocyclic systems have been developed: chromeno[4,3‐ d ]pyridines, chromeno[4,3‐ b ]pyridines, pyrano[3,2‐ c ]chromenes and imidazo[1,2‐ a ]pyridines (Scheme 1, part a) [7] .…”