Supervisor: Yeung Ying YeungThe aim of my project was to develop chiral chalcogen-centered organocatalysts to effect asymmetric halocyclization reactions utilizing the interaction between chalcogen and halogen. The halocyclization reaction is a very important organic transformation due to its useful products in various areas, while the catalytic asymmetric version of this process was underexploited.Bifunctional catalysis strategy was adopted in most of the previous reported publications, which focus mainly on the O-type cyclization reactions. Starting from a chiral natural product-mannitol, the monofunctional cyclic selenium catalysts were constructed. After intensive investigations, this series of catalysts was proved to be efficient in the asymmetric bromocyclization of trisubstituted unsaturated sulfonamide substrates, and the resulting pyrrolidines can be readily transformed to piperidines with excellent diastereoselectivity and enantiospecificity.

A bioactive molecule which is an oligopeptide analogue was constructed in 18 steps.

Supervisor: Wu SongThe aim of my project was to find compounds that have potent inhabiting activity towards the protein tyrosine phosphatase 1B (PTP1B), which plays an important role in the negative regulation of insulin signaling pathway, thus is a potential target for the treatment of diabetes and obesity. Around 60 target compounds were synthesized and tested for the inhibition of PTP1B, six of which have promising bioactivity (IC50≤1.0 uM), which was helpful to the further development of selective inhibitors of PTP1B.