Over the past three decades, considerable progress has been made in the development of methods to construct sp carbon-nitrogen (C-N) bonds using palladium, copper or nickel catalysis. However, the incorporation of alkyl substrates to form sp C-N bonds remains one of the major challenges in the field of cross-coupling chemistry. Here we demonstrate that the synergistic combination of copper catalysis and photoredox catalysis can provide a general platform from which to address this challenge. This cross-coupling system uses naturally abundant alkyl carboxylic acids and commercially available nitrogen nucleophiles as coupling partners. It is applicable to a wide variety of primary, secondary and tertiary alkyl carboxylic acids (through iodonium activation), as well as a vast array of nitrogen nucleophiles: nitrogen heterocycles, amides, sulfonamides and anilines can undergo C-N coupling to provide N-alkyl products in good to excellent efficiency, at room temperature and on short timescales (five minutes to one hour). We demonstrate that this C-N coupling protocol proceeds with high regioselectivity using substrates that contain several amine groups, and can also be applied to complex drug molecules, enabling the rapid construction of molecular complexity and the late-stage functionalization of bioactive pharmaceuticals.

A mechanism that enables direct aldehyde C–H functionalization has been achieved via the synergistic merger of photoredox, nickel, and hydrogen atom transfer (HAT) catalysis. This mild, operationally simple protocol transforms a wide variety of commercially available aldehydes, along with aryl or alkyl bromides, into the corresponding ketones in excellent yield. This C–H abstraction coupling technology has been successfully applied to the expedient synthesis of the medicinal agent haloperidol.

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Multicomponent reactions (MCRs) have become a mainstay in both academic and industrial synthetic organic chemistry due to their step- and atom-economy advantages over traditional synthetic sequences 1 . Recently, bicyclo[1.1.1]pentane (BCP) motifs have come to the fore as valuable pharmaceutical bioisosteres of benzene rings, and, in particular, 1,3-disubstituted BCP moieties have become widely adopted in medicinal chemistry as para -phenyl ring replacements 2 . Often these structures are generated from [1.1.1]propellane via opening of the internal C─C bond, either through the addition of radicals or metal-based nucleophiles 3 - 13 . The resulting propellane-addition adducts are subsequently transformed to the requisite polysubstituted BCP compounds via a range of synthetic sequences that traditionally involve multiple chemical steps. While this approach has been effective to date, it is clear that a multicomponent reaction that enables single-step access to complex and diverse polysubstituted BCP products would be synthetically advantageous over the current stepwise approaches. Herein we report a one-step three-component radical coupling of [1.1.1]propellane to afford diverse functionalized bicycles using various radical precursors and heteroatom nucleophiles via a metallaphotoredox catalysis protocol. The reaction operates on short time scales (five minutes to one hour) across multiple (>10) nucleophile classes and can accommodate a diverse array of radical precursors, including those which generate alkyl, α-acyl, trifluoromethyl, and sulfonyl radicals. This method has been used to rapidly prepare BCP analogues of known pharmaceuticals, one of which has substantially different pharmacokinetic properties to those of its commercial progenitor.