Organocatalytic hydration of activated alkynes

Abstract

Hydration reactions consist of the introduction of a molecule of water into a chemical compound. This process is a particularly useful method to allow, for instance, the conversion of alkynes into carbonyls, which are strategic intermediates in the synthesis of a plethora of compounds. Herein we demonstrate that L-cysteine can catalyse the hydration of activated alkynes in a very effective and fully regioselective manner to access β-ketosulfones, amides and esters in aqueous conditions. The mild reaction conditions facilitated the integration with enzyme catalysis to access chiral β-hydroxy sulfones from the corresponding alkynes in a one-pot cascade process in good yields and excellent enantiomeric excess. These findings pave the way towards establishing a general method for metal-free, cost-effective, and more sustainable alkyne hydration processes