Acetalization reactions play significant roles in the synthetically important masking chemistry of carbonyl compounds. In their paper the authors demonstrate for the first time that tropylium salts can act as organic Lewis acid catalysts to facilitate acetalization and transacetalization reactions of a wide range of aldehyde substrates. This metal-free method works efficiently in both batch and flow conditions, prompting further future applications of tropylium organocatalysts in green synthesis.
As featured on the front cover of Green Chemistry Issue 17, Dr Vinh Nguyen tells us a little more about the artwork: “This graphic features a “superchemist” in safety goggles and white labcoat/cape holding a round-bottom flask. He is holding a heptagonal shield representing our tropylium ion. There are engravings on the shield denoting what chemicals can be used to protect the “carbonyl compound” on his chest.”