Fragment Couplings via CO₂ Extrusion–Recombination: Expansion of a Classic Bond-Forming Strategy via Metallaphotoredox

In this study we demonstrate that molecular fragments, which can be readily coupled via a simple, in situ ROCOR bond-forming reaction, can subsequently undergo metal insertion–decarboxylation–recombination to generate C_sp²–C_sp³ bonds when subjected to metalla­photo­redox catalysis. In this embodiment the conversion of a wide variety of mixed anhydrides (formed in situ from carboxylic acids and acyl chlorides) to fragment-coupled ketones is accomplished in good to high yield. A three-step synthesis of the medicinal agent edivoxetine is also described using this new decarboxylation–recombination protocol

Silyl Radical Activation of Alkyl Halides in Metallaphotoredox Catalysis: A Unique Pathway for Cross-Electrophile Coupling

A strategy for cross-electrophile coupling has been developed via the merger of photoredox and transition metal catalysis. In this report, we demonstrate the use of commercially available tris­(trimethylsilyl)­silane with metallaphotoredox catalysis to efficiently couple alkyl bromides with aryl or heteroaryl bromides in excellent yields. We hypothesize that a photocatalytically generated silyl radical species can perform halogen-atom abstraction to activate alkyl halides as nucleophilic cross-coupling partners. This protocol allows the use of mild yet robust conditions to construct C_sp³–C_sp² bonds generically via a unique cross-coupling pathway

A General Small-Scale Reactor To Enable Standardization and Acceleration of Photocatalytic Reactions

Photocatalysis for organic synthesis has experienced an exponential growth in the past 10 years. However, the variety of experimental procedures that have been reported to perform photon-based catalyst excitation has hampered the establishment of general protocols to convert visible light into chemical energy. To address this issue, we have designed an integrated photoreactor for enhanced photon capture and catalyst excitation. Moreover, the evaluation of this new reactor in eight photocatalytic transformations that are widely employed in medicinal chemistry settings has confirmed significant performance advantages of this optimized design while enabling a standardized protocol