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Free keywords:
MESO-EPOXIDES; ENANTIOSELECTIVE ADDITION; KINETIC RESOLUTION; CARBOXYLIC-ACIDS; TERTIARY THIOLS; BRONSTED ACIDS; ORGANOCATALYSIS; DESYMMETRIZATION; NITROALKENES; THIOETHERS
Abstract:
The synthesis of enantiopure thiols is of significant interest for industrial and academic applications. However, direct asymmetric approaches to free thiols have previously been unknown. Here we describe a novel organocascade that is catalyzed by a confined chiral phosphoric acid and furnishes O-protected β-hydroxythiols with excellent enantioselectivities. The method relies on an asymmetric thiocarboxylysis of meso-epoxides, followed by an intramolecular trans-esterification reaction. By varying the reaction conditions, the intermediate thioesters can also be obtained chemoselectively and enantioselectively.
