Visible-Light-Driven Heterocyclic Fluoroalkylation Via Electron Donor-Acceptor Complexes

Heterocyclic fluoroalkylation is initiated through a photochemical reaction involving an electron donor-acceptor complex. The reaction proceeds smoothly without requiring a photocatalyst, transition metal catalyst or additional oxidant. Through extensive experiments, we optimised the heterocyclic fluoroalkylation method and confirmed its versatility and effectiveness on various substrates. The process synthesises fluoroalkylated quinoxalinones and indolones with high efficiency and was successfully extended to gram-scale applications, highlighting its practical utility. Detailed mechanistic analyses, supported by density functional theory calculations elucidated the role of the electron donor-acceptor complexes and deciphered the distinct radical chain reaction mechanism inherent in the halogen-atom transfer pathway. Given the importance of fluoroalkyl groups in pharmaceuticals, this simple and efficient method promises substantial applications in medicinal chemistry and materials science. This study introduces a novel photochemical fluoroalkylation method for heterocycles via Electron Donor-Acceptor (EDA) complexes, bypassing the need for transition metal catalysts, photocatalysts, or external oxidants. Utilizing 395 nm LEDs, this method efficiently synthesizes fluoroalkylated quinoxalinones and indolones. The study highlights the pivotal role of EDA photoactivation, thoroughly documented through Density Functional Theory (DFT) studies and mechanistic experiments, thereby broadening the application of EDA complexes in chemical synthesis. image