807349-45-7Relevant academic research and scientific papers
Unsaturated aldehydes as alkene equivalents in the Diels-Alder reaction
Taarning, Esben,Madsen, Robert
supporting information; experimental part, p. 5638 - 5644 (2009/05/30)
A one-pot procedure is described for using α,β-unsaturated aldehydes as olefin equivalents in the Diels-Alder reaction. The method combines the normal electron demand cycloaddition with aldehyde dienophiles and the rhodium-catalyzed decarbonylation of aldehydes to afford cyclohexenes with no electron-with-drawing substituents. In this way, the aldehyde group serves as a traceless control element to direct the cycloaddition reaction. The Diels-Alder reactions are performed in a diglyme solution in the presence of a catalytic amount of boron trifluoride etherate. Subsequent quenching of the Lewis acid, addition of 0.3% of [Rh(dppp)2Cl] and heating to reflux achieves the ensuing decarbonylation to afford the product cyclohexenes. Under these conditions, acrolein, crotonaldehyde and cinnamaldehyde have been reacted with a variety of 1,3-dienes to afford cyclohexenes in overall yields between 53 and 88%. In these transformations, the three aldehydes serve as equivalents of ethylene, propylene and styrene, respectively.
Chemical transformation of substrates using nonmetallic, organic catalyst compositions
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Example 10, (2010/11/29)
A method is provided for catalytically transforming a functional group within a first reactant by reaction with a second reactant in the presence of a nonmetallic, organic catalyst composition composed of a heteroatom-containing activator and an acid, or a salt of a heteroatom-containing activator and an acid. Exemplary first reactants are α,β-unsaturated carbonyl compounds such as α,β-unsaturated ketones and α,β-unsaturated aldehydes. The heteroatom of the activator is a Group 15 or Group 16 element such as nitrogen, oxygen, sulfur or phosphorus, and exemplary heteroatom-containing activators are amines. Chiral heteroatom-containing activators can be used to catalyze enantioselective reactions, such that a chiral product is obtained from a chiral or achiral starting material in enantiomerically pure form.
