Tandem reaction between chalcone epoxides and 2-naphthyl ethers to construct complex naphtho[2,1-b]furans

Dihydronaphthofurans: synthetic strategies and applications

Dihydronaphthofurans (DHNs) are an important class of arene ring-fused furans which are widely found in many natural and non-natural products and drug candidates with relevant biological and pharmacological activities. Furthermore, vinylidene-naphthofurans exhibit photochromic properties when exposed to UV or sun light at room temperature. For these reasons, a vast array of synthetic procedures for the preparation of dihydronaphthofurans including annulation of naphthols with various reagents, cycloaddition reactions ([3 + 2], [4 + 1] and Diels-Alder), intramolecular transannulation, Friedel-Crafts, Wittig, Claisen rearrangement, neophyl rearrangement and other reactions under various conditions have been developed over the past decades. This review aims to describe the different strategies developed so far for the synthesis of dihydronaphthofurans and their applications. After a brief introduction to the types of dihydronaphthofurans and their biological activities, the different synthetic approaches such as chemical, photochemical, and electrochemical, methods are described and organized on the basis of the catalysts and the other reagents employed in the syntheses. The subsequent section focuses on biological and pharmacological applications and photochromic properties of the target compounds.

Synthesis of 3-Aryl-Benzo[b]Furans and 3-Aryl-Naphtho[b]Furans Using N-Propyl-4-Aza-1-Azoniabicyclo[2.2.2]Octane Chloride Immobilised on SiO2 as an Efficient and Reusable Catalyst

A new and convenient method is describe d for the synthesis of 3-aryl-benzo[ b]furans and 3-aryl-naphtho[ b]furans by the reaction of various α-bromoketones with phenols and 2-naphthols in the presence of n-propyl-4-aza-1-azoniabicyclo[2.2.2]octane chloride immobilised on SiO2. All products were obtained in high yields and short reaction times using solvent-free conditions and a reusable catalyst.

An efficient synthesis of naphtho[2,1-b]furan-2(1H)-ones catalysed by Nafion-H supported on silica-coated super paramagnetic iron oxide nanoparticles

A one-pot procedure is descibed for the synthesis of naphtho[2,1- b]furan-2(1 H)-ones via a multicomponent reaction of aryl aldehydes, hippuric acid, acetic anhydride and β-naphthol in the presence of Nafion-H supported on silica-coated superparamagnetic iron oxide nanoparticles under microwave irradiation. The catalyst can be recovered easily and reused several times without significant loss of catalytic activity.

A Novel pseudo-Four-Component Domino Reaction for the Synthesis of Naphtho[2,1-b]furan-2(1H)-ones Using a Nanocatalyst

In this article, an original one-pot method is utilized to synthesize a variety of derivatives of naphtho[2,1-b]furan-2(1H)-one via a pseudo-four-component domino reaction of aryl aldehydes, acetic anhydride, hippuric acids, and 2-naphthols catalyzed by HSW@SPIONs. This reaction illustrates an array of attractive features including, with particular interest in this report, a convenient and unique process of creating and utilizing a powerful recyclable nanocatalyst.