Photocatalytic asymmetric cross-dehydrogenative coupling of tetrahydroisoquinoline scaffolds

Tetrahydroisoquinoline (THIQ) scaffolds represent a significant family of nitrogen-containing heterocyclic compounds encountered in numerous natural alkaloids and drug molecules. Consequently, the development of elegant synthetic strategies for their synthesis and functionalization into value-added compounds, providing dual reactivity and activity, is highly desired but challenging. Recently, the synergistic combination of asymmetric catalysis and visible-light-induced photoredox catalysis for accessing complex molecules of potential therapeutic interest has emerged as a fascinating key area in organic chemistry. In this context, and considering the importance of THIQ derivatives, herein, we aim to demonstrate a summary of the recent progress achieved in the direct cross-dehydrogenative coupling of THIQ scaffolds by employing combined photoredox and asymmetric catalysis. Besides disclosing the advantages, limitations, and challenges associated with the presented works, their drawbacks and mechanistic rationalizations are also discussed.