The Development of New Methodologies for Practical Synthesis of Pharmaceuticals in Batch and Flow Process
The development of methodologies has been studied for synthesis of useful products, such as natural products and pharmaceuticals. In particular, carbonyl addition is one of the fundamental reactions forming C–C bonds in organic chemistry to construct structurally complex organic molecules from small molecules. For this useful carbonyl addition, transition metal catalyzed redox-triggered C–C bond forming reactions of alcohols have been developed via transfer hydrogenation. Combined redox events are more efficient in terms of step and atom-economy by delivering nucleophile-electrophile pairs in situ from π-unsaturates and alcohols, respectively. Furthermore, transition metal catalyzed redox triggered C–C couplings bypass the need of stoichiometric (organo)metallic reagents.
In the decade, flow chemistry has been also one of the powerful ways to develop efficient methodologies. Recent reports have detailed the attractive features of transferring a photochemical reaction to flow process. Due to high molar extinction coefficients of most photocatalysts, photoredox-catalyzed transformations carried out on a preparative scale in batch are frequently, “photon-limited”, in accordance with the Beer-Lambert law. To overcome this issue in batch, flow process would be a means of reducing reaction times and expanding the substrate scope due to increased photon concentration through decreasing the path length and increasing the surface area of the reaction vessel. Herein, this seminar introduces several works regarding transition metal catalyzed redox triggered C–C couplings in batch and photochemistry in continuous flow process.