Recent Advancements in Photocatalytic Synthesis of Five Membered Nitrogen Heterocycles and Their Derivatives.

Photocatalytic synthesis of heterocycles has emerged as a versatile strategy in organic synthesis. Among various heterocycles, five membered heterocycles such as pyrroles, indoles and their derivatives have great significance based on their pharmaceutical applications. Diverse photocatalysts have shown great potential in synthesis of nitrogen heterocycles either through radical-based mechanism or via energy transfer pathway. Compared to other synthesis routes, the photocatalytic approach offers unique advantages including green synthesis, one step reaction and approaching the challenging reaction to prepare nitrogen heterocycles. Tuning redox potential or tailoring triplet state energies of photocatalysts can play crucial role in selective and efficient synthesis of nitrogen heterocycles. In this review we have briefly covered the latest developments demonstrated for photocatalytic synthesis of five membered nitrogen heterocycles including pyrroles and indoles and their derivatives. We also discuss the existing challenges, bottlenecks and the future outlook in this field, aiming to advance photocatalytic strategies of producing five membered nitrogen heterocycles as valuable tools in modern synthetic chemistry.