104144-10-7

Upstream product

• 124-38-9 carbon dioxide 
• 106-99-0 buta-1,3-diene 
• 75-56-9 methyloxirane 

Relevant academic research and scientific papers

PALLADIUM- AND RHODIUM-CATALYZED SYNTHESIS OF ESTERS BY REACTION OF BUTADIENE, CARBON DIOXIDE, AND OXIRANES

Butadiene, carbon dioxide and ethylene oxide interact in the presence of palladium or rhodium catalysts to give (2'-hydroxyethyl)2-ethylidene-4,6-heptadienoate in a "one pot" reaction.When propylene oxide was used, two related isomeric esters with an additional methyl group in the alcohol part of the ester were obtained, in yields of up to 24percent.Kinetic investigations suggest that the reaction occurs via the lactone 2-ethylidene-6-hepten-5-olide.The products are accounted for in terms of a mechanism involving the coordination of the oxirane to an allylic transition metal carboxylate complex and insertion of the oxirane to give an allylic alkoxy complex.Elimination of the products occurs via a hydrogen migration step.

Possibilities of Controling Transition Metal-catalyzed Reactions of 1,3-Dienes with Carbon Dioxide

The reaction of butadiene with carbon dioxide using homogeneous palladium, ruthenium, and nickel catalysts affords the C9-lactone 2-ethylidene-6-hepten-5-olide (3) in yields up to 59percent.In contrast, rhodium catalysts give rise to the formation of the C13-lactone 2-ethyl-2,4,9-undecatrien-4-olide (10) by connection of three molecules of butadiene with carbon dioxide.The C13-lactone can also be synthesized by the rhodium-catalyzed reaction of the C9-lactone with butadiene. - Trialkylphosphines containing a CHR2-group bound to the phosphorus and phosphorous or arsenic ylides proved to be extraordinarily effective and selective ligands in the synthesis of the C9-lactone.This effect is interpreted by an activation of carbon dioxide by means of the ligand.In the reaction of butadiene with CO2, allyl and carboxylate complexes of the transition metals are proposed to be the mechanistic intermediates.In fact, the carboxylate complex bis(2-ethylidene-4,6-heptadienoato)bis(triisopropylphosphane)palladium (22) was isolated by a stoichiometric reaction starting with the C9-lactone.This complex, of which the structure was determined by X-ray analysis, proved to be an excellent one-component catalyst in the reaction of butadiene and CO2. - Isoprene and piperylene can be linked up with butadiene and carbon dioxide yielding new δ-lactones (32, 34, 36).The insertion of carbon dioxide takes place at the allyl group which is formed by the butadiene.

THE SYNTHESIS OF ORGANIC CHEMICALS BY CATALYTIC REACTIONS OF CARBON DIOXIDE

Different reactions are discussed in which carbon dioxide adds to unsaturated hydrocarbons after activation by transition metal catalysts.Alkynes react in the presence of nickel or rhodium complexes to yield substituted pyrones.Alkenes are also described to react with CO2 yielding acids and esters; however,the proof, that carbon dioxide is really involved in this reaction, is still lacking.The best studied reaction is the chemistry of carbon dioxide and butadiene.Using palladium, nickel and ruthenium catalysts γ- and δ-lactones are formed by the reaction of two molecules of butadiene and one molecule of CO2.The catalyst and the reaction parameters could be optimized thus enabling the synthesis of the δ-lactone in an industrial scale.A mechanism is proposed in which a carboxylate complex is discussed to be key intermediate, and a similar palladium complex could be isolated in a related stoichiometric experiment.Using rhodium catalysts, a γ-lactone is formed in which three molecules of butadiene are connected to one molecule of carbon dioxide.Also the co-reaction of butadiene, isoprene and CO2 yields novel lactones.All these products may become of interest as fine chemicals, for instance fragrances.Another possible use of the lactones is their conversion into open-chained products.The splitting of the δ-lactone yields new carboxylic acids and esters with hydroxy or methoxy substituents, which may become useful starting molecules for chemical syntheses.