Light‑Driven Copper Trick Makes Fancy Sulfur Molecules

A new way to build special sulfur compounds uses light and copper. Instead of the usual method, chemists now link a sulfur atom to a carbon that is already part of a simple hydrocarbon. This process happens when the copper catalyst, fed with light energy, pulls electrons from the hydrocarbon. The result is a chiral sulfilimine that can be produced in large amounts and with high purity. The key idea is to let the reaction happen outside the copper’s immediate reach, a so‑called outer‑sphere S-H2 step.Computer models support this picture: the sulfur atom hops onto the carbon in a single, clean motion. Because the reaction is driven by light, it avoids harsh chemicals and works at room temperature. The new method can use everyday fuels like propane or butane as starting materials. That means the sulfilimines can be made cheaply and sustainably, opening doors for drug makers and material scientists. The approach also gives chemists a fresh tool to study how chirality is created in sulfur chemistry.