Intramolecular vicinal Frustrated Lewis Pairs (FLPs) have played a significant role in the activation of small molecules, and their stabilities and reactivities are found to strongly depend on the nature of the bridging units. This work reports a new carborane based FLP, 1-PPh-2-BPh-1,2-CBH (), which reacts with an equimolar amount of -RNCHC[triple bond, length as m-dash]CH (R = Me, Et, Ph) at room temperature to give C[triple bond, length as m-dash]C triple bond addition products 1,2-[PPhC(RNCH)[double bond, length as m-dash]CHBPh]-1,2-CBH () in high yields. Compounds react further with two equiv. of -RNCHC[triple bond, length as m-dash]CH (R = Me, Et) at 60-70 °C to give unprecedented stereoselective tri-insertion products, 3,3,6,6-tetrahydronaphtho[1,8]borole tricycles (), in which one of the aryl rings from arylacetylene moieties has been dearomatized with the formation of four stereocenters including one quaternary carbon center. It is noted that the phosphine unit functions as a catalyst during the reactions. After trapping and structural characterization of a key intermediate, a reaction mechanism is proposed, involving sequential alkyne insertion and 1,2-boryl migration.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8179331 | PMC |
http://dx.doi.org/10.1039/d0sc05755j | DOI Listing |
Prev Med Rep
January 2025
Center for Advanced Practice, OSF HealthCare, Peoria, IL, USA.
Objective: The benefits of mobile applications in the prenatal period remain understudied. This study assessed associations between the Pregnancy Postpartum Support Program (PPSP), a digital wraparound service, and maternal and infant outcomes in a Medicaid population.
Methods: A retrospective analysis was conducted on pregnant patients with Medicaid insurance who received care and delivered in a Midwestern United States healthcare system between 8/1/2022-8/15/2023, comparing outcomes among those who did versus did not opt for PPSP enrollment.
Angew Chem Int Ed Engl
January 2025
Sichuan University - Wangjiang Campus: Sichuan University, Polymer Research Institute, CHINA.
Covalent adaptable networks (CANs) offer innovative solutions for the reprocessing and recycling of thermoset polymers. However, achieving a balance between easy reprocessing and creep resistance remains a challenge. This study focuses on designing and synthesizing polyurethane (PU) materials with tailored properties by manipulating the stereochemistry of diamine chain extenders.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
January 2025
Department of Chemistry, Dalhousie University, 1459 Oxford Street, P.O. Box 15000, Halifax, NS B3H 4R2, Canada.
We extend our previous work on the energetics and mechanisms of fragmentation in the mass spectrometry of triacylglycerols (TAGs). Previously, we proposed viable mechanisms for the collision-induced fragmentation of lithiated tripropionylglycerol using triple-quadrupole mass spectrometry. In this work, we used a QqLIT mass spectrometer to study both double- and triple-stage spectra from a range of TAGs having acid chains of types AAA (identical acid chains), AAB, ABA, and ABC, with chain lengths of 6-18 carbon atoms; we also studied some TAGs having a single double bond in the Δ-9 position.
View Article and Find Full Text PDFJ Mol Model
January 2025
Shanxi Jiangyang Chemical Industry Corporation, Taiyuan, 030041, Shanxi, China.
Context: To address the issue that the output charge in existing Deflagration to Detonation Transition (DDT) detonators cannot withstand high temperatures of 200 °C, and to improve the output performance of the detonator, a CL-20 (Hexanitrohexaazaisowurtzitane) based polymer bonded explosive (PBX) was investigated as the primary charge material for the detonator. To select the most suitable binder for thermal resistance, molecular dynamics (MD) simulations were employed to evaluate the performance of different binders at various crystal planes and temperatures. The results indicate that among the five PBXs models, CL-20/F exhibits the highest binding energy and the shortest bond initiation length at both ambient and elevated temperatures.
View Article and Find Full Text PDFPNAS Nexus
January 2025
Thrust of Earth, Ocean and Atmospheric Sciences Function Hub, The Hong Kong University of Science and Technology (Guangzhou), Guangzhou 511453, China.
Modulating the electronic structure of noble metals via electronic metal-support interaction (EMSI) has been proven effectively for facilitating molecular oxygen activation and catalytic oxidation reactions. Nevertheless, the investigation of the fundamental mechanisms underlying activity enhancement has primarily focused on metal oxides as supports, especially in the catalytic degradation of volatile organic compounds. In this study, a novel Pt catalyst supported on nitrogen-doped carbon encapsulating FeNi alloy, featuring ultrafine Pt nanoparticles, was synthesized.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!