Isocyanoacetates as Synthetic Platform Towards Natural Products and Biologically Relevant Scaffolds

Buyck, Thomas (Buyck, Thomas Bertrand Pascal Marie)
Advisor: Zhu, Jieping

My PhD work started with the development of a racemic access to trigonoliimine B, an hexacyclic alkaloid isolated in 2010. After having explored different strategies, we reported a 7-step synthesis of this natural product. This synthesis features a challenging and unprecedented Bischler-Napieralski reaction for the formation of a 7-membered ring with the concurrent creation of an exocyclic imine at the last step. The choice of sulfolane as solvent for this transformation was critical to the success. Aiming at upgrading our synthesis towards an enantioselective version, we developed an enantioselective synthesis of α-quaternary α-amino acids. The Michael addition between α-aryl isocyanoacetates and phenyl vinyl selenone catalyzed by a quinine derivative affords enantioenriched Michael adducts. Due to the nature of the functional groups, these adducts are easily transformed to useful scaffolds such as pyrrolidinones and oxindoles. We also demonstrated the synthetic utility of this transformation by using it for the enantioselective total synthesis of (+)- and (-)-trigonoliimine A. With the idea to further demonstrate the efficiency of this reaction for natural product synthesis, we are trying to develop the first total synthesis of (+)-hinckdentine A. Finally, during our investigations on the Michael adduct, we observed the formation of 1,3-oxazinan-2-one. We implemented an integrated one-pot process to access biologically relevant 1,3-oxazinan-2-one. We also studied the reaction mechanism demonstrating an unprecedented triple role of phenyl selenonyl group as an electron withdrawing group, a leaving group and a latent oxidant.


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