Cabrera-Pardo, J.R. et al. Nat. Chem. 5, 423–427 (2013).

Discovery of novel chemical reactions is a fundamental focus of the field of organic chemistry. Cabrera-Pardo et al. report a high-throughput methodology for reaction discovery, using the power of laser desorption/ionization mass spectrometry (MS). In this approach, the researchers place an inert, polyaromatic MS label on a reactant such that any products that form will also contain the label. This facilitates their easy detection in the resulting mass spectrum without requiring purification. The authors carefully selected an MS label that would also promote selective desorption/ionization so as to circumvent the need for a typical matrix, which would make low–molecular weight products difficult to detect by MS. Applying the method to screen nearly 700 different reactant combinations, they discovered two novel benzannulation reactions, which may find use in organic synthesis.