Publication: Visible light Driven Alkylation and Cascade Annulation Using N-(acyloxy) phthalimides and Aryl Diazo Esters
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2024-12-23
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Indian Institute of Technology, Jodhpur
Abstract
N-heterocycles are fundamental architectures in medicinal chemistry and materials science and are the core structure of many drugs and biologically active compounds. The aim of this work was to develop green and sustainable strategies for preparing and tailoring N- heterocycles from alkylating agents, such as N-(acyloxy) phthalimides and aryl diazo esters. We describe a visible-light-mediated (4 + 2) cycloaddition reaction to construct fused tetrahydroquinolines using an electron donor-acceptor (EDA) complex. This metal and catalyst- free strategy employs alkyl N-(acyloxy)phthalimides and N-substituted maleimides to obtain products with outstanding regioselectivity, broad functional group compatibility, and excellent yields. Leveraging this success, we developed an unprecedented organophotoredox-catalyzed method for direct C–H alkylation of 3,4-dihydroquinoxaline-2-ones with NHPI esters. This strategy results in mild, high-yielding, and scalable access to sp³-enriched scaffolds, which is pivotal for pharmaceutical endeavors. We further developed a green and sustainable N- alkylation of azauracils using aryl diazo esters in our laboratory. This catalyst and additive-free protocol provided mild compatibility for imide alkylation with many substrates and functional groups. Notably, this useful transformation allows rare three-component reactions to occur in cyclic ethers and will thus likely facilitate the modification of biologically pertinent molecules and natural products. This study offers a new green approach to organic synthesis by employing sustainable synthetic methods. These methodologies take advantage of visible light to induce selective transformations with low-energy input, thus contributing to synthesizing complex molecules of interest in medicinal chemistry.
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Hota, Sudhir Kumar (2020).Visible light Driven Alkylation and Cascade Annulation Using N-(acyloxy) phthalimides and Aryl Diazo Esters (Doctor's thesis).Indian Institute of Technology, Jodhpur