Project Description

Among the emerging paradigms in green synthetic chemistry, visible-light-mediated photochemistry has established itself as one of the most powerful and sustainable platforms for the construction of complex molecular architectures. This Ph.D. project aims to develop transition-metal-free radical cascade cyclization reactions under visible light to build structurally diverse heterocyclic scaffolds. Conventional synthetic routes to such frameworks rely heavily on transition-metal catalysis, stoichiometric oxidants, and high temperatures, which raise concerns about cost, sustainability, and operational simplicity, particularly for pharmaceutically relevant molecules. Over the past decade, visible-light photoredox catalysis has emerged as a cleaner alternative, driving reactions through single-electron transfer (SET) and energy-transfer (ET) pathways under mild conditions, with excellent atom economy and access to bond activations that are difficult to achieve through traditional thermal chemistry. Building on this progress, organic photoredox catalysts along with photocatalyst-free electron donor-acceptor (EDA) complex strategies have opened sustainable ways to generate reactive radical intermediates that can trigger complex cascade cyclizations. Despite these advances, the use of such strategies to access important heterocyclic scaffolds commonly found in pharmaceuticals and bioactive molecules is still underexplored, offering significant opportunities for new methodological developments. This project introduces novel concepts in photochemistry by exploiting both organic-photocatalyst-driven SET pathways and EDA-complex activation strategies, which upon visible-light excitation generate radical intermediates under mild and operationally simple conditions.

We plan to design tailored organic photocatalysts and EDA-complex systems to carry out selective radical addition, tandem cyclization, and C-C/C-N bond-forming cascades on biaryl vinyl ethers, o-(allyloxy)arylaldehydes, N-allylbromodifluoroacetamides, and related substrates under visible light. The goal is to develop simple, efficient, and step-economical methods that convert readily available starting materials into valuable heterocyclic products of significant pharmaceutical and medicinal-chemistry relevance, providing a sustainable alternative to traditional transition-metal-catalyzed routes.