Copper(II) Trifluoromethanesulfonate as an Efficient, Versatile, and Dual-Purpose Catalyst for the Regioselective Acetylation of l -Sorbose under Neat and Solvent-Directed Conditions

High Resolution Image Download MS PowerPoint Slide Herein, we report that copper(II) trifluoromethanesulfonate [Cu(OTf) 2 ], a stable, versatile, and dual-purpose catalyst, efficiently catalyzed the acetylation of l -sorbose under various conditions following metal trifluoromethanesulfonate screening. Regioselectivity is critically governed by solvents: solvent-free reactions favor the open-chain keto -sorbopentaacetate, whereas coordinating solvents direct acetylation toward the cyclic α- l -sorbopyranosyl tetraacetate. These findings underscore the pivotal role of solvents in steering reaction pathways, enabling selective and sustainable synthesis of structurally distinct sugar derivatives while using a minimal amount of catalysts.