Highly Convergent Synthesis of Intensively Blue Emissive Furo[2,3‐c]isoquinolines by a Palladium‐Catalyzed Cyclization Cascade of Unsaturated Ugi Products
Аннотация:Abstract A convergent and diversity‐oriented approach to the unusual furo[2,3‐ c ]isoquinoline scaffold is presented. This serendipity‐driven approach is characterized by an Ugi multicomponent reaction, which gives the substrate for a palladium‐catalyzed insertion–alkynylation–cycloisomerization cascade to provide the furo[2,3‐ c ]isoquinolines in moderate to high yield. Upon UV excitation, all representatives are intensively blue luminescent, as observed by the naked eye, and quantitative fluorescence spectroscopy reveals a considerable effect of the substitution pattern on the quantum yields. The electronic structure is semiquantitatively rationalized by DFT and time‐dependent DFT calculations.
