When developing new drugs, one thing is particularly important: finding and producing the right molecules that can be used as active ingredients. The key elements of some drugs, such as penicillin, are small, tri- or quadripartite ring molecules. A team led by Prof Frank Glorius from the Institute of Organic Chemistry of the University of Münster (Germany) has now developed a method for efficiently converting readily available basic materials into such small, high-grade ring molecules. The product has a structure reminiscent of a line drawing of a house, hence its name "housane." The reaction is triggered by a photocatalyst that transfers light energy to the molecules to enable the conversion.