Herein, we introduce the efficient synthesis of Q-proline (Q-Pro) based, metal-binding macrocycles (QPM), which can display up to nine functional groups. Synthesis of eight QPM was achieved through standard Fmoc-SPPS and peptoid chemistry. QPM are disordered in the absence of a metal cation, as evidenced by NMR and a crystal structure of <b>QPM-3</b> obtained through racemic crystallization. Addition of metal cations cause these macrocycles to adopt ordered, uniform core structures regardless of the functional groups. Alkylation of QPM allows for addition of reactive functional groups as the final step in a synthesis. Interestingly, the addition of secondary functional groups to the hydantoin amide position (R₂) converts the proline ring from Cg-endo to Cg-exo, due to steric interactions.

Herein, we introduce the efficient synthesis of Q-proline (Q-Pro) based, metal-binding macrocycles (QPM), which can display up to nine functional groups. Synthesis of eight QPM was achieved through standard Fmoc-SPPS and peptoid chemistry. QPM are disordered in the absence of a metal cation, as evidenced by NMR and a crystal structure of QPM-3 obtained through racemic crystallization. Addition of metal cations cause these macrocycles to adopt ordered, uniform core structures regardless of the functional groups. Alkylation of QPM allows for addition of reactive functional groups as the final step in a synthesis. Interestingly, the addition of secondary functional groups to the hydantoin amide position (R2) converts the proline ring from C-endo to C-exo, due to steric interactions. 27 Pro 3-2 60 No >98 28 3-4 60 Yes 50 29 3-4 60* Yes >98 QP9 QP9 30 3-4 60* Yes >98 QP15

The versatile isocyanide building block Asmic, anisylsulfanylmethylisocyanide, reacts with aldehydes and ketones in a BF 3 •OEt 2 -mediated condensation to afford thioimidoyl-substituted 2,5-dihydrooxazoles. The condensation is distinguished from related base and transition-metal-catalyzed [3 + 2] processes in proceeding via the condensation of aldehydes and ketones with 2 equiv of an isocyanide followed by a molecular rearrangement that installs four new bonds. BF 3 •OEt 2 mediates an analogous condensation of Asmic with imines to generate N-substituted dihydroimidazoles. Mechanistically, BF 3 • OEt 2 activates the isocyanide to facilitate deprotonation evolving to a zwitterion that traps π-electrophiles in a formal [3 + 2] process. A second deprotonation−condensation with Asmic initiates a structural rearrangement involving a sulfanyl elimination− addition transposition sequence. The resulting dihydrooxazoles and dihydroimidazoles contain a thioimidate that serves as a diversification point for further elaboration.

We report the first tetrapodal pentadentate ligand composed of five N‐heterocyclic carbene donors. The proto‐ligand [CC4H5Me](OTf)3 (3) is formed in good yields from commercially available reagents. Upon removal of 5 proton equivalents from 3 with bulky non‐nucleophilic bases a dianionic penta‐carbene framework is provided in good yields as a dilithium complex CC4MeLi2 (4). Addition of FeCl3 to a solution of 4 formed in situ provides CC4MeFeCl (5) in moderate yield. Solution‐state magnetism measurements of 5 are consistent with a S=1/2 Fe(III) center. The related diamagnetic Fe(II) compound CC4MeFe (6) can be formed through reduction of 5 using KC8 though poor solubility characteristics have hampered its formation on a preparative scale and full characterization.

The Front Cover shows selected tetrapodal‐pentadentate “butterflies” taking flight. First noted as bearing resemblance to butterflies by Paine and Nordlander, these 5‐coordinate frameworks have found applications in areas such as H2 evolution catalysis, N2 reduction chemistry, and as scaffolds to support high‐valent metal‐oxo compounds. Our contribution to this topology consists of a carbon butterfly composed of five N‐heterocyclic carbene donors bridged by arylborate linkers to provide a dianionic framework upon removal of five protons. More information can be found in the Research Article by J. J. Scepaniak and co‐workers.

Quaternary ammonium compounds (QACs) serve as a first line of defense against infectious pathogens. As resistance to QACs emerges in the environment, the development of next-generation disinfectants is of utmost priority for human health. Balancing antibacterial potency with environmental considerations is required to effectively counter the development of bacterial resistance. To address this challenge, a series of 14 novel biscationic quaternary phosphonium compounds (bisQPCs) have been prepared as amphiphilic disinfectants through straightforward, high-yielding alkylation reactions. These compounds feature decomposable or “soft” amide moieties in their side chains, anticipated to promote decomposition under environmental conditions. Strong bioactivity against a panel of seven bacterial pathogens was observed, highlighted by single-digit micromolar activity for compounds P6P-12A,12A and P3P-12A,12A. Hydrolysis experiments in pure water and in buffers of varying pH revealed surprising decomposition of the soft QPCs under basic conditions at the phosphonium center, leading to inactive phosphine oxide products; QPC stability (>24 h) was maintained in neutral solutions. The results of this work unveil soft QPCs as a potent and environmentally conscious new class of bisQPC disinfectants.

Substituted oxazoles and imidazoles are synthesized in one pot from the isocyanide building block Asmic (anisylsulfanylmethyl isocyanide), an alkyl halide, and an acid chloride or nitrile, respectively. The modular assembly employs sequential deprotonation−alkylation and deprotonation−acylation or imination of Asmic, followed by an unusual carbon−sulfur bond cleavage to construct the azole. The strategy is robust, highly efficient, and affords C4−C5 disubstituted oxazoles or imidazoles in a single operation

Thermolysis of ω-iodoalkyl-β-siloxyalkenenitriles in DMSO triggers an oxidative cyclization cascade that affords highly oxygenated hydrindanones, decalones, and undecanones. The cyclization cascade is highly unusual on three counts: the cyclization installs a contiguous array of tertiary–quaternary–tertiary centers, thermolysis equilibrates a quaternary center, and the enolsilyl ether crossed-aldol proceeds without a catalyst.