Catalytic enantioselective protonation (EP) is a straightforward and effective approach to construct enantioenriched carbonyl compounds containing a tertiary stereocenter at its α-position, which has been widely applied in organic synthesis and medicinal chemistry. This field has significant advances in recent decades, and relevant reviews based on substrate category, catalytic system and reaction type have been reported successively. In this paper, new developments in this field are updated and summarized since 2019, which are classied into the directly catalytic asymmetric protonation of performed enolates and the enantioselective protonation of in situ enolates, α-carbanion, or α-radical intermediates, involving a variety of substrate categories, catalytic systems, activation modes, as well as catalytic strategies and means. It is expected that these studies can inspire chemists to continuously contribute to this field and further promote the development of carbonyl chemistry, asymmetric catalysis and other related fields, and provide facile and efficient access to high-value chiral molecules, including natural products and their intermediates, drugs, drug candidates and so on.

Key words: asymmetric catalysis, protonation, chiral carbonyl compound, α-tertiary stereocenter, enolate, organocatalysis, Lewis acid catalysis