Research Projects

Functionalized pyrazolines, isoxazolines, and their aromatic variants are five-membered aza-heterocyclic structural motifs found in numerous natural products with vital properties such as antidepressants, anti-inflammatory, antiviral, and antibacterial. These molecules have been commercialized as drugs and agrochemicals, and serve as important synthons for the preparation of natural products and organic synthesis. These heterocycles have become attractive targets for the development of new chemical reactions. To the best of our knowledge, there is no direct method for the preparation of either racemic or chiral 4/5-heterofunctionalized pyrazolines and isoxazolines, nor for the construction of 4/5-heterofunctionalized pyrazoles and isoxazoles. A general catalytic asymmetric method for the preparation of 4/5-heterofunctionalized pyrazolines/isoxazolines and a direct method to access pyrazoles/isoxazoles are highly desired. Chiral hypervalent iodines have emerged as an alternate mode of catalysis for challenging transformations and synthesis due to their unique mode of activations. However, the use of these class of catalysts for the preparation of chiral pyrazolines and isoxazolines or their aromatic variants remains unknown. The proposed approach focuses on developing the first I(III) catalyzed enantioselective methods for the preparation of 4/5-heterofunctionalized pyrazolines and isoxazolines, the first I(III) catalyzed direct method for the preparation of 4/5-heterofunctionalized isoxazoles and pyrazoles, and synthetic transformations of pyrazolines, isoxazolines, isoxazoles, and pyrazoles to produce potentially useful entities.