Light‐Induced Domino and Multicomponent Reactions: How to Reach Molecular Complexity without a Catalyst

Abstract

Achieving high molecular complexity can be not trivial, but the exploitation of domino reactions provides an atom‐ and step‐economical method to reach this target. Over the past decades, a lot of efforts have been put on the development of photocatalytic cascades employing both metal‐based and purely organic catalysts. Despite the effectiveness of these protocols, catalyst‐ and additive‐free light‐induced domino reactions are gaining momentum thank to their efficiency, operational simplicity and sustainability. The increasing number of papers published on this field in the last years is a proof of the appeal of these transformations. In this Review, we discuss domino and multicomponent reactions mediated by light with a focus on photocatalyst‐ and additive‐free processes. The most recent advances in the synthesis of complex nitrogen‐, oxygen‐, sulphur/selenium‐heterocycles together with multicomponent cascades are analysed with an emphasis on both experimental and mechanistic studies.

Photocatalytic Enantioselective Radical Cascade Multicomponent Minisci Reaction of β‐Carbolines Using Diazo Compounds as Radical Precursors

“…These enantioselective cascade Minisci‐type reactions offer several advantages, including increased efficiency, rapid assembly of molecular diversity, and the versatile ability to access complex structures that may be challenging to synthesize through stepwise approaches. [ 13 ] However, the development of enantioselective multicomponent Minisci reactions remains in its infancy. It is important to note that such asymmetric cascade Minisci reactions present ongoing challenges, requiring compatible reactivity of each component and precise control over chemo‐/stereochemistry at each step.…”