Aqueous sodium tosylate: a sustainable medium for alkylations

Abstract

Typical alkylation reactions produce significant amounts of undesired salt and solvent waste. Herein, we report an efficient alkylation protocol utilising aqueous sodium tosylate (NaTos) solutions as a hydrotrope-containing medium. The methodology represents an inexpensive and straightforward approach for preparing alkyl aryl ethers, thioethers and N-alkylated tosyl amides in high yields under mild conditions. The generated reaction waste, aqueous NaTos salt, was repurposed as a reaction medium in subsequent steps. This medium was recycled ten times without any significant change in the yield, providing an improved environmental factor over various literature examples. Under similar conditions, commonly applied solvents furnished the products with lower yields and more waste.