Catalytic reaction discovery accelerated by polyaromatic labelling

Scientists in the US have developed a novel way to accelerate the discovery of new catalytic reactions by incorporating a label in one of the reactants that makes it easy to identify the reactant and any products derived from it in the reaction mixture without chromatographic separation. The technique was described in Nature Chemistry by Sergey Kozmin and colleagues belonging to the Chicago Tri-Institutional Centre for Chemical Methods and Library Development.

They illustrated the method by the reaction of siloxyalkynes with 23 different reactants in the presence of 29 individual reagents over a AuNCMe-SbF₆ catalyst, giving a total of 696 discrete experiments in 96-well format. The siloxyalkynes were pre-labelled with pyrene, which was not eliminated during the reactions, so that it could act to promote selective laser desorption/ionisation for mass spectrometric analysis in the absence of a matrix solution and facilitate product identification.

The method led to the discovery of two new benzannulation reactions in which [4+2] cycloaddition was followed by ring opening and aromatisation, a previously unknown benzannulation of alkynes that could lead further to substituted salicylic acids and functionalised naphthols.