Tandem nucleophilic reaction of 1,3-dicarbonyl compounds to methyl α-bromoacrylate: [3+2]heteroannulation leading to hydrofuran derivatives

Strategies for the synthesis of furo-pyranones and their application in the total synthesis of related natural products

The furo-pyranone framework is widely present in the molecular structure of various biologically potent natural products and un-natural small molecules, and it represents a valuable target in synthetic organic chemistry and medicinal chemistry.

Synthesis of functionalized trans-2,3-disubstituted-hexahydrobenzofurans in an aqueous medium using triethanolamine as catalyst

A one-pot, efficient synthesis of seven novel trans-2,3-diacylated hexahydrobenzofuran derivatives has been achieved via a three-component condensation of N-(1-benzyloxycarbonylmethyl)quinolinium bromide with 5,5-dimethyl-1,3-cyclohexanedione (dimedone) and an aromatic aldehyde in the presence of catalytic amounts of triethanolamine in water under reflux conditions. The attractive features of the method are excellent yields and high purity, short reaction times, easy work-up, and use of an inexpensive and non-toxic catalyst.

Diastereoselective Synthesis of Functionalised Trans-Tetrahydrobenzofuran-4-Ones in an Aqueous Medium by using DABCO as an Efficient Catalyst

A one-pot, efficient synthesis of 11 novel 2,3-diacylated trans-tetrahydrobenzofuran-4-one derivatives has been achieved via a three-component condensation of a N-(4-halophenacyl)-pyridinium bromide, a cyclic 1,3-diketone such as 5,5-dimethyl-1,3-cyclohexanedione (dimedone) or cyclohexane-1,3-dione and an arylglyoxal in the presence of catalytic amounts of 1,4-diaza-bicyclo[2.2.2]octane (DABCO) in water under reflux conditions. The attractive features of the method are excellent yields and high purity, short reaction times, easy work-up, and use of an inexpensive and non-toxic catalyst.

Synthesis of a series of novel 2,3-dihydrofurano-γ-lactone derivatives using DABCO as catalyst in an aqueous medium

A one-pot, green and efficient synthesis of twelve trans-2-(4-chlorobenzoyl)-3-aryl-3,6-dihydrofuro[3,4- b]furan-4-ones has been achieved via a three-component condensation of 2-[2-(4-chlorophenyl)-2-oxoethyl)]isoquinolinium bromide with furan-2,4-dione and an araldehyde in the presence of catalytic amounts of 1,4-diaza-bicyclo[2.2.2]octane (DABCO) in water under reflux conditions.

Synthesis of a series of novel 2,3-dihydrofuranonaphthoquinone derivatives

A green and highly efficient synthesis of 12 novel trans-2-(4-chlorobenzoyl)-3-aryl-2,3-dihydronaphtho[2,3- b]furan-4,9-diones has been achieved via a three-component, one-pot condensation of 2-[2-(4-chlorophenyl)-2-oxoethyl)]isoquinolinium bromide with 2-hydroxy-1,4-naphthoquinone and an aromatic aldehyde in the presence of catalytic amounts of choline hydroxide in water under reflux conditions. The advantages of this method are a short reaction time, high yields and the avoidance of any hazardous organic solvent. Therefore, this procedure can be classified as green chemistry.

A clean, simple and efficient synthesis of trans-[3-(aryl)-2,3-dihydrofuro[3,2-h] quinolin-2-yl]-(4-chlorophenyl)methanones

We report a green and efficient method for the synthesis of trans-[3-(aryl)-2,3-dihydrofuro[3,2- h]quinolin-2-yl]-(4-chlorophenyl) methanones from the condensation of 2-[2-(4-chlorophenyl)-2-oxoethyl)]isoquinolinium bromide with 8-hydroxyquinoline and an aromatic aldehyde in the presence of catalytic amounts of choline hydroxide in water at reflux conditions. This new protocol employing choline hydroxide, which is a green and inexpensive catalyst, offers advantages such as mild reaction conditions, short reaction time, high yields and does not involve any hazardous solvent. Therefore, this procedure can be classified as green chemistry.

Green synthesis of trans-2-(4-chlorobenzoyl)-5-hydroxy-3-(aryl)-2,3-dihydrobenzofuran-4,7-diones

A green and efficient synthesis of trans-2-(4-chlorobenzoyl)-5-hydroxy-3-(aryl)-2,3-dihydrobenzofuran-4,7-diones has been achieved in excellent yield via a three-component one-pot condensation of 2-[2-(4-chlorophenyl)-2-oxoethyl)]isoquinolinium bromide with 2,5-dihydroxy-1,4-benzoquinone and aromatic aldehydes in the presence of catalytic amounts of choline hydroxide in water under reflux conditions. The salient features of this protocol are the short reaction time, the high yields and it does not involve any hazardous organic solvent.

DABCO as an Efficient Catalyst for the Diastereoselective Synthesis of trans-(4-chlorophenyl)-7-aryl-6,7-dihydro-[1,3]dioxolo[4,5-f]benzofuran-6-yl) Methanone in an Aqueous Medium

A three-component one-pot condensation of 2-[2-(4-chlorophenyl)-2-oxoethyl)]isoquinolinium bromide with benzo[1,3]dioxol-5-ol and an aromatic aldehyde in the presence of catalytic amounts of 1,4-diaza-bicyclo[2.2.2]octane (DABCO) in refluxing water gives trans-(4-chlorophenyl)-7-aryl-6,7-dihydro-[1,3]dioxolo[4,5- f]benzofuran-6-yl)methanone in excellent yield and in short time.

Highly efficient construction of bisspirooxindoles containing vicinal spirocenters through an organocatalytic modified Feist-Bénary reaction

We have developed an organocatalytic modified Feist-Bénary reaction of cyclic dicarbonyl compounds, isatins and cyclic α-bromo dicarbonyl compounds. This method affords bisspirooxindole-fused dihydrofurans containing two vicinal spiro centers. To the best of our knowledge, employing cyclic α-halo dicarbonyl compounds for the synthesis of bisspirooxindole-fused dihydrofurans has not been previously reported.

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.

Stereoselective synthesis of tetrasubstituted 2,3-dihydrofurans by one-step cyclization of beta-ketosulfides of benzothiazole and aldehydes in ionic liquids

A stereoselective synthesis of tetrasubstituted 2,3-dihydrofurans was carried out in n-butylpyridinium tetrafluoroborate ([bpy(+)][BF(4)(-)]) as solvent. The reaction proceeds smoothly in one step starting from simple materials such as aldehydes and beta-ketosulfides of benzothiazole. A comparison between several ionic liquids (ILs) is presented, and the role of the benzothiazolyl moiety is discussed. Workup proved to be very easy and recycling of IL possible.