Functionalization of aldehydes via N-heterocyclic carbene and base organic catalysts

• Main Author: Yang, Ruojie
• Other Authors: Robin Yonggui Chi
• Format: Theses and Dissertations
• Language: English
• Published: Nanyang Technological University 2014
• Subjects: DRNTU::Science::Chemistry::Organic chemistry::Organic synthesis
• Online Access: https://hdl.handle.net/10356/61843
• Institution: Nanyang Technological University

In this thesis, direct and efficient functionalization of aldehydes with organocatalysts towards synthetic attractive molecules is presented. Chapter II describes the direct α-functionalization of simple aldehydes under oxidative NHC catalysis and the direct generation of ester enolates by using simple nonfunctionalized aldehydes as substrates. The same transformation with only catalytic amount of quinone-derived oxidant can be realized by using much cheaper terminal oxidants MnO2, providing an economic solution for large scale industrial synthesis. Chapter III presents the [3+2] annulations of isatin and β-branched unsaturated aldehyde catalyzed by N-heterocyclic carbene. Synthetic attractive spirocyclic oxindole products are synthesized in generally good yield and diastereoand enantioselectivity. Followed in chapter IV, the first base catalyzed in-situ generation of enesulfonamide is discussed. This enamide derivative underwent facile formal [4+2] addition reactions with α,β-unsaturated imines, producing highly substituted tetrahydropyridines as single diasteromer, which possess huge potential in the synthesis of pharmaceutical and biological compounds.