More Like this

1. Scalable and safe synthetic organic electroreduction inspired by Li-ion battery chemistry

   https://doi.org/10.1126/science.aav5606  

   Peters, Byron K.; Rodriguez, Kevin X.; Reisberg, Solomon H.; Beil, Sebastian B.; Hickey, David P.; Kawamata, Yu; Collins, Michael; Starr, Jeremy; Chen, Longrui; Udyavara, Sagar; et al (February 2019, Science)

   Reductive electrosynthesis has faced long-standing challenges in applications to complex organic substrates at scale. Here, we show how decades of research in lithium-ion battery materials, electrolytes, and additives can serve as an inspiration for achieving practically scalable reductive electrosynthetic conditions for the Birch reduction. Specifically, we demonstrate that using a sacrificial anode material (magnesium or aluminum), combined with a cheap, nontoxic, and water-soluble proton source (dimethylurea), and an overcharge protectant inspired by battery technology [tris(pyrrolidino)phosphoramide] can allow for multigram-scale synthesis of pharmaceutically relevant building blocks. We show how these conditions have a very high level of functional-group tolerance relative to classical electrochemical and chemical dissolving-metal reductions. Finally, we demonstrate that the same electrochemical conditions can be applied to other dissolving metal–type reductive transformations, including McMurry couplings, reductive ketone deoxygenations, and epoxide openings. 

   more » « less
2. Electronic Rearrangement in Steps of Reductive Elimination of Polar Electrophiles Leads to Refinement of Redox Events

   https://doi.org/10.1021/acs.organomet.3c00102  

   Basemann, Kevin; Becker, Jennifer J; Windus, Theresa L; Gagné, Michel R (August 2023, Organometallics)

   The oxidative addition/reductive elimination of polar molecules such as methyl iodide at late metal centers has a strongly supported SN2 mechanism for many key organometallic complexes, including important industrial catalysts. In the reductive elimination direction, it is proposed that a ligand initially dissociates, typically a halide, followed by subsequent nucleophilic attack at the ligand trans to the now vacant site. The prevailing view is the metal reduction occurs upon transferring the electrophile in the SN2 step. Herein, we report the use of an ensemble of computational techniques to characterize the electronic structure of the reactants and intermediates along this reductive elimination pathway. These calculations demonstrate, unexpectedly, that the initiating loss of an anionic ligand from the octahedral highly oxidized structure leads to an electronic rearrangement that shifts electron density from the apical ligand back toward the metal resulting in an inversion of the electron flow between the metal and apical ligand. The anisotropic shift in electron density to the metal disproportionately affects the apical position, which is best described as a Pt → Me dative bond. With this Pt → Me bonding description, our interpretation of the IUPAC oxidation state formalism would assign the intermediate as PtII. Although counterintuitive, the formal and functional reduction of the metal thus occurs upon halide dissociation. 

   more » « less
3. Cu‐Catalyzed Hydroxymethylation of Unactivated Alkyl Iodides with CO To Provide One‐Carbon‐Extended Alcohols

   https://doi.org/10.1002/anie.201801814  

   Zhao, Siling; Mankad, Neal P. (April 2018, Angewandte Chemie International Edition)

   Abstract We have developed a reductive carbonylation method by which unactivated alkyl iodides can be hydroxymethylated to provide one‐carbon‐extended alcohol products under Cu‐catalyzed conditions. The method is tolerant of alkyl β‐hydrogen atoms, is robust towards a wide variety of functional groups, and was applied to primary, secondary, and tertiary alkyl iodide substrates. Mechanistic experiments indicate that the transformation proceeds by atom‐transfer carbonylation (ATC) of the alkyl iodide followed in tandem by two CuH‐mediated reductions in rapid succession. This radical mechanism renders the Cu‐catalyzed system complementary to precious‐metal‐catalyzed reductive carbonylation reactions. 

   more » « less
4. Transition metal-mediated reductive coupling of diazoesters

   https://doi.org/10.1039/C9CC03771C  

   Grass, Amanda; Stoian, Sebastian A.; Lord, Richard L.; Groysman, Stanislav (July 2019, Chemical Communications)

   The first transition metal mediated reductive coupling of diazoesters through the terminal nitrogens is reported. The resulting tetrazene-bridged bis(diazenylacetate) serves as a novel dinucleating ligand to iron(III). DFT calculations suggest that the reductive coupling takes place via a κ 2 intermediate, which induces significant radical character on the terminal nitrogen. 

   more » « less
5. A Coordination Polymer of Vaska's Complex as a Heterogeneous Catalyst for the Reductive Formation of Enamines from Amides

   https://doi.org/10.1002/anie.202301611  

   Griffin, Samuel E.; Domecus, Grant P.; Flores, Clarissa E.; Sikma, R. Eric; Benz, Lauren; Cohen, Seth M. (April 2023, Angewandte Chemie International Edition)

   Abstract Low‐valent metal–organic frameworks (LVMOFs) and related materials have gained interest due to their potential applications in heterogeneous catalysis. However, of the few LVMOFs that have been reported, none have shown catalytic activity. Herein, a low‐valent metal‐organic material constructed from phosphine linkers and Ir^Inodes is reported. This material is effectively a crystalline, insoluble analogue of Vaska's complex. As such, the material reversibly binds O₂and catalyzes the reductive formation of enamines from amides. 

   more » « less