Asymmetric Synthesis of O-Tosylated α,β-Epoxy Alcohols via Organocatalytic Desymmetrization of Triols

Chiral epoxides are broadly acknowledged as versatile building blocks in organic synthesis, owing their propensity to undergo regioselective ring-opening reactions that enable the construction of highly functionalized architectures with precise stereochemical control. Despite the substantial progress achieved in their preparation, general and efficient methodologies for accessing chiral 1,1- disubstituted terminal epoxides remain limited. Herein, we report the first enantioselective catalytic synthesis of O-tosylated α,β- epoxy alcohols through desymmetrization of triols. Conversion of the two primary alcohol moieties into suitable leaving groups enables the remaining tertiary alcohol to undergo a selective intramolecular SN2 process promoted by a bifunctional organocatalyst, furnishing enantioenriched epoxides.4 The resulting products constitute valuable intermediates for the synthesis of biologically relevant molecules through selective post-functionalization.