Executive Summary : | Allenes represent a highly privileged class of synthons due to their unique cumulative double bond structure. The incorporation of additional functional groups into the allene moiety holds the promise of enhancing the system's intriguing reactivity patterns in both catalytic and non-catalytic processes. Notably, the Lewis base-catalyzed annulations of allenoates, first reported by Lu, demonstrated the extensive exploration of this chemistry. similarly, the reactivity of ynamides and enamides, with their delicate balance between stability and reactivity, has been the subject of much research interest. Both ynamides and allenoates exhibit certain similarities in their reactivity, owing to the resonance form of the 'ketenium' structure displayed by ynamides. Nevertheless, the vast landscape of unexplored territories in allenoate and ynamide chemistry, especially concerning catalytic systems, presents exciting opportunities for discovery. Therefore, the primary goal of this proposal is to advance the field of allenoate, ynamide, and enamide chemistry by introducing novel annulation and rearrangement reactions, leading to the creation of valuable organic scaffolds and small molecules.
A relatively recent development in organic synthesis is the utilization of visible-light-promoted photocatalysis, which has gained popularity for its sustainability and potential in green chemistry. This approach leverages visible light to photoexcite photocatalysts, facilitating single electron transfer (sET) processes that generate highly reactive free-radical intermediates. These intermediates can then be harnessed for building molecular complexity from simple building blocks. Despite the promising prospects of visible-light photocatalysis, its application in conjunction with allenoates, ynamides, and enamides remains relatively unexplored. Therefore, the systematic exploration of this one-electron chemistry with these substrates holds great value for contemporary organic synthesis. |