The microwave-assisted organocatalyzed rearrangement of Propargyl vinyl ethers to salicylaldehydes derivatives

Trabajo presentado en el 19th European Symposium of Organic Chemistry, celebrado en Lisboa del 12 al 16 de julio de 2015.
Propargyl vinyl ethers constitute a privileged group of small size, densely functionalized and readily accessible linear scaffolds. The main key to the chemical reactivity encoded in these structures is the [3,3]-sigmatropic rearrangement (propargyl Claisen rearrangement) shown in Scheme 1A, which takes place irreversibly and under thermodynamic control to generate the allene 2 which isomerizes to dienal. We have developed a microwave-assisted, catalytic (imidazole 10 mol-%) and scalable methodologyto transform these allenes into salicylaldehyde motives supported on a broad range of topologies, which spanned from simple aromatic monocycles to complex fused polycyclic systems. The reaction manifold is depicted in Scheme 1B. We have performed a theoretical study of this reaction which is in full agreement with the observed experimental results. The reaction scope and the proposed mechanism will be commented in our presentation.
This research was supported by the Spanish Ministerio de Economía y Competitividad (MINECO), and the European FEDER and Regional Development Fund (CTQ2011-28417-C01-02). L. Cotos and D.M. thank MICINN and CSIC for a FPI and a JAE-PRE grant respectively.