Sustainable synthetic routes to deuterium-labelled organic compounds using immobilized and recyclable (bio)catalysts

Deuterium(D)-labelled organic compounds are used in many applications e.g., as therapeutic agents, internal standards in drug discovery and development, and new functional materials including dyes, catalysts, and light emitters. Conventionally, the synthesis of D-labelled compounds relies on (bio)catalysts due to their regio- and stereoselectivity, mild reaction conditions, and treatment of a broad scope of substrates. However, most (bio)catalysts are expensive to prepare/isolate, and some contain precious metals (PMs), e.g., Ir, Pd, whose markets are unpredictable, and which need to be separated from the products at great expense, post-reaction. With the general shift away from traditional ‘make-use-dispose’ approaches to ones that are less wasteful, the use of recyclable catalysts in both batch and continuous flow systems are increasingly employed. In this work, we comprehensively and critically review the catalysts and immobilization and recycling strategies implemented for the preparation of D-labelled organic compounds. Our aim is to highlight the most effective advances and expose the gaps in the literature to inform future research.