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1. Generation and Rearrangement of N , O ‐Dialkenylhydroxylamines for the Synthesis of 2‐Aminotetrahydrofurans

   https://doi.org/10.1002/ange.201800908  

   Son, Jongwoo ; Reidl, Tyler W. ; Kim, Ki Hwan ; Wink, Donald J. ; Anderson, Laura L. ( April 2018 , Angewandte Chemie)

   A new diastereoselective route to 2‐aminotetrahydrofurans has been developed fromN,O‐dialkenylhydroxylamines. These intermediates undergo a spontaneous C−C bond‐forming [3,3]‐sigmatropic rearrangement followed by a C−O bond‐forming cyclization. A copper‐catalyzedN‐alkenylation of anN‐Boc‐hydroxylamine with alkenyl iodides, and a base‐promoted addition of the resultingN‐hydroxyenamines to an electron‐deficient allene, provide modular access to these novel rearrangement precursors. The scope of this de novo synthesis of simple nucleoside analogues has been explored to reveal trends in diastereoselectivity and reactivity. In addition, a base‐promoted ring‐opening and Mannich reaction has been discovered to covert 2‐aminotetrahydrofurans to cyclopentyl β‐aminoacid derivatives or cyclopentenones.

    

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2. Cooperative activation of O–H and S–H bonds across the Co–P bond of an N-heterocyclic phosphido complex

   https://doi.org/10.1039/C8DT05052J  

   Poitras, Andrew M. ; Bezpalko, Mark W. ; Foxman, Bruce M. ; Thomas, Christine M. ( February 2019 , Dalton Transactions)

   Metal–ligand cooperation has proven to be a viable concept for σ bond activation and catalysis, however there are few examples involving phosphorus as an active participant in bond cleavage. The reactivity of E–H bonds (E = S, O) across a metal–phosphorus bond of a cobalt( i ) center ligated by a tridenate N-heterocyclic phosphido (NHP − ) ligand with diphosphine sidearms, (PPP) − , has been explored. Addition of PhOH to (PPP)CoPMe 3 ( 1 ) cleanly affords (PP OPh P)Co(H)PMe 3 ( 2 ), in which the O–H bond was heterolytically cleaved across the M–P NHP bond. Addition of PhSH to 1 first generates (PP H P)Co(SPh)PMe 3 ( 3 ), which undergoes an intermolecular rearrangement to generate (PP SPh P)Co(H)PMe 3 ( 4 ) as the thermodynamic product. A comparison with a related platinum( ii ) system reveals the subtle effects that variations in metal intrinsic properties can have on metal–ligand bifunctional σ bond activation processes. 

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3. Dinitrogen activation at chromium by photochemically induced CrII–C bond homolysis

   https://doi.org/10.1039/d4cc02387k  

   Duletski, Olivia L ; Platz, Duncan ; Pollock, Charlie J ; Mosquera, Martín A ; Arulsamy, Navamoney ; Mock, Michael T ( June 2024 , Chemical Communications)

   Exposure of (POCOP^tBu)Cr(Bn) to 427 nm blue light under 1 atm N₂ promoted Cr–C_Bn bond homolysis and led to N₂ activation forming [(POCOP^tBu)Cr]₂(μ-N₂).

    

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4. Functionalized vinyldiazo compounds: New players in asymmetric catalysis

   https://doi.org/10.1016/j.checat.2023.100770  

   Bao, M ; De_Angeles, L ; Rada, MS ; Baird, M ; Arman, H ; Wherritt, D ; Doyle, MP ( October 2023 , Chem Catalysis)

   The catalytic uses of metal carbenes for addition, insertion, and cycloaddition reactions are dependent on their carbene precursor. The limited methods available for the preparation of diazo esters, which are the most common carbene precursors, restricts their ability to impart structural diversity in metal carbene reactions. Here we report a new methodology for the preparation of diverse vinyldiazoacetate esters and their effective uses in highly enantiocontrolled cyclopropanation, N-H bond insertion, O-H bond insertion, and [3+2] cycloaddition reactions. 1,2,3-Triazine 1-oxides with a sp3-C-H bond at the 5-position undergo base catalyzed Dimroth-type rearrangement to form multiply substituted oximidovinyldiazoacetates in high yields at or below room temperature, and these diverse vinyldiazo compounds undergo catalytic metal carbene transformations to produce oximidovinylcyclopropanes, α-oximidovinyl-α-amino acids and α-hydroxy acids, as well as tricyclic indole derivatives in high yields and enantioselectivities. The new access to vinyldiazo compounds has applicability to a vast array of metal carbene transformations. 

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5. Crystal structure of 4-methyl- N -propylbenzenesulfonamide

   https://doi.org/10.1107/S2056989020007756  

   Stenfors, Brock A. ; Collins, Rachel C. ; Duran, Jonah R. ; Staples, Richard J. ; Biros, Shannon M. ; Ngassa, Felix N. ( July 2020 , Acta Crystallographica Section E Crystallographic Communications)

   The crystal structure of the title sulfonamide, C 10 H 15 NO 2 S, comprises two molecules in the asymmetric unit. The S=O bond lengths of the sulfonamide functional group range from 1.428 (2) to 1.441 (2) Å, with S—C bond lengths of 1.766 (3) Å (for both molecules in the asymmetric unit), and S—N bond lengths of 1.618 (2) and 1.622 (3) Å, respectively. When both molecules are viewed down the N—S bond, the propyl group is gauche to the toluene moiety. In the crystal structure, molecules of the title compound are arranged in an intricate three-dimensional network that is formed via intermolecular C—H...O and N—H...O hydrogen bonds. The crystal structure was refined from a crystal twinned by inversion. 

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