Journal of the American Chemical Society, Vol.134, No.25, 10659-10663, 2012
Enhancing the Scope of the Diels-Alder Reaction through Isonitrile Chemistry: Emergence of a New Class of Acyl-Activated Dienophiles
alpha,beta-Unsaturated imides, formylated at the nitrogen atom, comprise a new and valuable family of dienophiles for servicing Diels-Alder reactions. These systems are assembled through extension of recently discovered isonitrile chemistry to the domain of alpha,beta-unsaturated acids. Cycloadditions are facilitated by Et2AlCl, presumably via chelation between the two carbonyl groups of the N-formyl amide. Applications of the isonitrile/Diels-Alder logic to the IMDA reaction, as well as methodologies to modify the N-formyl amide of the resultant cycloaddition product, are described. It is expected that this easily executed chemistry will provide a significant enhancement for application of Diels-Alder reactions to many synthetic targets.