Exploiting the Distal Reactivity of Indolylmethylenemalononitriles
Since the advent of modern organocatalysis at the turn of the 21st century, asymmetric aminocatalysis, which uses chiral amines as catalysts, has been at the center of an explosive growth, culminating in the implementation of a myriad of high-impact stereoselective organic transformations, many of which are represented by efficient and creative organocatalytic formal [4+2] cycloadditions. In particular, the use of aminocatalysts proved to be an extremely useful strategy to induce the transient generation of highly reactive ortho-quinodimethane (oQDM) intermediates from simple heteroaromatic compounds (e.g., methylindole-, methylpyrrole- or methylfuran-based heterocycles) while directing the pericyclic reactions with suitable dienophiles toward a highly stereoselective pathway. The authors
approach published recently provides straightforward access to complex, chiral polycyclic architectures, which would be difficult to synthesize by other catalytic methods, and should open new synthetic pathways to complex chiral molecules using nontraditional disconnections.
Read here the full article for free Exploiting the Distal Reactivity of Indolylmethylenemalononitriles: An Asymmetric Organocatalyzed [4+2] Cycloaddition with Enals enables the Assembly of Elusive Dihydrocarbazoles