Facile Grignard Reaction Demonstration Using Molecular Sieved Dried Solvent

Abstract

Methods involving C–C bond formation are continuously being innovated due to their importance in the creation and modification of important organic molecules. The classic Grignard reaction demonstrates C–C bond formation with reagents that are usually accessible in undergraduate laboratory classes. Oftentimes, to make the Grignard reaction viable, the reactions are assisted by heating at elevated temperatures or with the use of a catalyst accompanied by solvents that have been dried using highly reactive sodium metal (Na⁰)─conditions which increase the risk of a laboratory fire or explosion. For this work, a method to conduct Grignard reactions under mild conditions utilizing sand-paper-polished Mg ribbons and solvent dried using molecular sieves was developed. The conscientious, accessible, and easy-to-follow preparation of both the solvent and the Mg ribbons is found to contribute more to the percent conversion of reagents to products. The average percent conversion with the proposed method ranged from 76.8% to 99.5% based on ¹H NMR results. This makes the Grignard demonstration possible even for the most humid, tropical locations.