Anti-Markovnikov hydrochlorination: Iron/ sulfur catalysts activated by mild blue light add chlorine atoms to organic molecules at lower cost

https://phys.org/news/2025-01-eco-friendly-chlorine-method-drug.html

"no harsh chemicals, high temperatures, or purification challenges... room temperature, efficient, precise targeting of chlorine placement on molecules creating highly pure products by selectively attaching chlorine atoms to less-reactive parts of starting molecules... can additionally use heavy water to incorporate deuterium to make certain drugs potentially more effective, and last longer in the body by increasing stability... medications, plastics, pesticides and other essential products"