Richard M. Pagni

Sonogashira coupling and cyclization reactions on alumina: a route to aryl alkynes, 2-substituted-benzo[b]furans and 2-substituted-indoles

Abstract A solventless, microwave-enhanced Sonogashira coupling reaction of aromatic iodides with terminal alkynes on potassium fluoride doped alumina in the presence of palladium powder, cuprous iodide, and triphenylphosphine has been developed. The reaction can be utilized to prepare aryl alkynes in excellent yields. The coupling of o-iodophenol with terminal alkynes leads to the formation 2-substituted-benzo[b]furans. Whereas the coupling of o-iodoanilines with terminal alkynes generates indole products. An in situ desilylation reaction was also developed.

Rapid microwave-enhanced, solventless Sonogashira coupling reaction on alumina

Abstract A microwave-enhanced, solventless Sonogashira coupling reaction has been developed. Terminal alkynes couple with aryl or alkenyl iodide on palladium-doped alumina in the presence of triphenylphosphine and cuprous iodide to provide high yields of products.

Ultrastable Superbase-Derived Protic Ionic Liquids

Protic ionic liquids are synthesized via proton transfer from acids to organic bases. One of the key issues associated with conventional protic ionic liquids is the thermal instability resulting from temperature-induced decomposition via reverse proton transfer. This shortcoming significantly hampers the use of these protic ionic liquids in separations, electrochemical capacitors, fuel cells, and so forth. Herein we show that it is possible to prepare protic ionic liquids with thermal stabilities approaching those of common aprotic ionic liquids. Our new class of protic ionic liquids, derived via integrated neutralization and metathesis of superbasic phosphazenes or guanidines, exhibits exceptionally low vapor pressures at 150 degrees C while being stable to strong alkali agents such as aqueous KOH, suggesting potential in energy-related applications, including electrochemical capacitors and PEM-type fuel cells.

The acid-catalyzed and uncatalyzed hydrolysis of nitriles on unactivated alumina

Abstract Nitriles are selectively converted into amides on unactivated alumina, with the surface hydroxyl groups serving as the source of water.

Microwave-assisted, solventless Suzuki coupling reactions on palladium-doped alumina

The generation of carbon–carbon bonds forms the backbone of organic synthesis. In recent years, the use of boron-containing precursors in palladium-assisted bond forming reactions (the Suzuki reaction) has gained prominence because of the vast array of functionally substituted boron containing reagents available to the organic chemist. The development of a solventless, microwave-assisted Suzuki reaction utilizing a readily recyclable solid catalyst offers numerous benefits. These include the straightforward recovery of both product and catalyst, conservation of energy through the use of microwave irradiation, simple commercial scale up, and low waste protocols due to the absence of solvents.

The diels-alder reaction of cyclopentadiene and methyl acrylate on γ,-alumina

Abstract The Diels-Alder reaction of cyclopentadiene and methyl acrylate has been run on γ-alumina. The ratio of endo to exo products is strongly dependent on the activity of the alumina. The exo adduct was also found to epimerize slowly to the endo adduct by a mechanism involving the retro-Diels-Alder reaction of the exo adduct.

Photochemistry of anthracene in water

Abstract Photolysis of anthracene (350 nm) in aerated water yields endoperoxide and 9,10-anthraquinone as the major primary photoproducts. Photolysis of anthracene in oxygen-deficient aqueous solutions yields the three isomers of 10,10′-dihydroxy-9,9′,10,10′-tetrahydro-9,9′-bianthryl as the primary photoproduct. Involvement of a cation radical mechanism is suggested.

The effect of alumina on the Diels-Alder reactions of cyclopentadiene with menthyl acrylate and dimenthyl fumarate.

Abstract Alumina catalyzes the Diels-Alder reactions of cyclopentadiene with optically active menthyl acrylate and dimenthyl fumarate. Significant diastereoselectivity is observed in each case.

The cycloaddition reactions of unsaturated esters with cyclopentadiene on γ-alumina

Abstract The Diels-Alder reaction of cyclopentadiene (CP) with methyl acrylate (MA), dimethyl maleate (DMM), and dimethyl fumarate (DMF) on alumina of varying activity has been examined. The diastereoselectivity of the reaction of CP with MA is markedly dependent on the activity of the alumina. Two factors account for these changes: (1) the nature and number of the catalytic sites on the surface, and (2) the observed reversibility of the Diels-Alder reaction on the more activated alumina. The reaction of CP with MA has been used to measure the Ω value of the surface of unactivated alumina.

The macrocyclization reaction of terminal dibromoalkanes with sulfide on alumina. The use of a solid support as an alternative to the high dilution technique.

Abstract The reaction of a series of terminal dibromoalkanes with S −2 on Al 2 O 3 has been examined. The use of a solid support for the macrocyclization represents a viable alternate procedure to the more traditional high dilution technique in solution. The cyclizations also occur with thioacetamide on unactivated alumina.