Seminar “2-Oxo-aldehyde-derived Ugi adducts: applications in heterocyclic chemistry, materials science and asymmetric synthesis”
14 April at 16.30 (Moscow time)
2-Oxo-aldehyde-derived Ugi adducts possess increased nucleophilicity of the peptidyl position compared to the standard Ugi adducts owing to an additional electron-withdrawing group introduced with 2-oxo-aldehyde. Several research groups have taken advantage of this property by designing new routes for the diversity-oriented synthesis of heterocycles through the post-Ugi transformations involving the peptidyl reactive site. We have also succeeded with advancing this approach by exploiting the triple bond as a complementary electrophilic partner in a number of enolization-driven post-Ugi cyclizations leading to the assembly of pyrrol-2-one core. Furthermore, we were the first who recognized that the applicability of 2-oxo-aldehyde-derived Ugi adducts is not limited to heterocyclic chemistry. For example, we have taken advantage of a
The resulting O,O-chelated boron complexes turned out to be strong solid-state emitters featuring clear aggregation-induced emission (AIE) characteristics, the property that was first described by Tang and coworkers as opposite to the aggregation-caused quenching (ACQ). Very recently, we have explored a possibility of an asymmetric modification of 2-oxo-aldehyde-derived Ugi adducts towards the formation of enantioenriched peptidomimetics. In this way, we were able to introduce a new strategy for controlling the stereochemistry in Ugi adducts. Instead of controlling stereochemistry directly during the Ugi reaction we have shown that the chiral center at the peptidyl position can be stereodefined through the post-Ugi functionalization. In order to achieve that, we have utilized the enantioselective electrophilic fluorination of carbonyl compounds promoted by Cinchona alkaloid derivatives developed independently by Shibata, Takeuchi and coworkers and by the group of Cahard.