LAUSR

Regioselective reactions allow the differentiation between two or more chemically identical reactive centers within the same molecule. They are highly desirable transformations in organic synthesis, as they avoid additional chemical operations and sophisticated protection/deprotection strategies. In this context, enzymes, which present exquisite selectivity and reactivity, have been widely employed as catalysts in numerous regioselective transformations. This review focuses on two recently developed biocatalytic processes that present outstanding regioselectity: the transaminase-catalyzed asymmetric amination of di- and triketo compounds, and the stereoselective C–C coupling between phenol derivatives, ammonia and pyruvate for the synthesis of tyrosine analogues, catalyzed by tyrosine phenol lyases. Additionally, elegant and straightforward cascades that have combined the aforementioned biotransformations with other enzymatic and/or chemocatalytic processes are compiled in this contribution. Overall, this review aims to provide a general view of the synthetic possibilities that two relatively recently described regio- and stereoselective biotransformations can provide.