An improved synthesis of functionalized biphenyl-based phosphine ligands

LASP to the Future of Atomic Simulation: Intelligence and Automation

Atomic simulations aim to understand and predict complex physical phenomena, the success of which relies largely on the accuracy of the potential energy surface description and the efficiency to capture important rare events. LASP software (large-scale atomic simulation with a Neural Network Potential), released in 2018, incorporates the key ingredients to fulfill the ultimate goal of atomic simulations by combining advanced neural network potentials with efficient global optimization methods. This review introduces the recent development of the software along two main streams, namely, higher intelligence and more automation, to solve complex material and reaction problems. The latest version of LASP (LASP 3.7) features the global many-body function corrected neural network (G-MBNN) to improve the PES accuracy with low cost, which achieves a linear scaling efficiency for large-scale atomic simulations. The key functionalities of LASP are updated to incorporate (i) the ASOP and ML-interface methods for finding complex surface and interface structures under grand canonic conditions; (ii) the ML-TS and MMLPS methods to identify the lowest energy reaction pathway. With these powerful functionalities, LASP now serves as an intelligent data generator to create computational databases for end users. We exemplify the recent LASP database construction in zeolite and the metal-ligand properties for a new catalyst design.

Data-driven discovery of active phosphine ligand space for cross-coupling reactions

The design of highly active catalysts is a main theme in organic chemistry, but it still relies heavily on expert experience. Herein, powered by machine-learning global structure exploration, we forge a Metal-Phosphine Catalyst Database (MPCD) with a meticulously designed ligand replacement energy metric, a key descriptor to describe the metal-ligand interactions. It pushes the rational design of organometallic catalysts to a quantitative era, where a ±10 kJ mol-1 window of relative ligand binding strength, a so-called active ligand space (ALS), is identified for highly effective catalyst screening. We highlight the chemistry interpretability and effectiveness of ALS for various C-N, C-C and C-S cross-coupling reactions via a Sabatier-principle-based volcano plot and demonstrate its predictive power in discovering low-cost ligands in catalyzing Suzuki cross-coupling involving aryl chloride. The advent of the MPCD provides a data-driven new route for speeding up organometallic catalysis and other applications.

Carboiodanation of Arynes: Organoiodine(III) Compounds as Nucleophilic Organometalloids

Organic iodine(III) compounds represent the most widely used hypervalent halogen compounds in organic synthesis, where they typically perform the role of an electrophile or oxidant to functionalize electron-rich or -nucleophilic organic compounds. In contrast to this convention, we discovered their unique reactivity as organometallic-like nucleophiles toward arynes. Equipped with diverse transferable ligands and supported by a tethered spectator ligand, the organoiodine(III) compounds undergo addition across the electrophilic C-C triple bond of arynes while retaining the trivalency of the iodine center. This carboiodanation reaction can forge a variety of aryl-alkynyl, aryl-alkenyl, and aryl-(hetero)aryl bonds along with the concurrent formation of an aryl-iodine(III) bond under mild conditions. The newly formed aryl-iodine(III) bond serves as a versatile linchpin for downstream transformations, particularly as an electrophilic reaction site. The amphoteric nature of the iodine(III) group as a metalloid and a leaving group in this sequence enables the flexible and expedient synthesis of extended π-conjugated molecules and privileged biarylphosphine ligands, where all of the iodine(III)-containing compounds can be handled as air- and thermally stable materials.

Palladium-Catalyzed C-P Bond-Forming Reactions of Aryl Nonaflates Accelerated by Iodide

An iodide-accelerated, palladium-catalyzed C-P bond-forming reaction of aryl nonaflates is described. The protocol was optimized for the synthesis of aryl phosphine oxides and was found to be tolerant of a wide range of aryl nonaflates. The general nature of this transformation was established with coupling to other P(O)H compounds for the synthesis of aryl phosphonates and an aryl phosphinate. The straightforward synthesis of stable, isolable aryl nonaflates, in combination with the rapid C-P bond-forming reaction allows facile preparation of aryl phosphorus target compounds from readily available phenol starting materials. The synthetic utility of this general strategy was demonstrated with the efficient preparation of an organic light-emitting diode (OLED) material and a phosphonophenylalanine mimic.

Short syntheses of 1-substituted dibenzothiophene derivatives

The 1-substituted dibenzothiophene motif is an unusual substitution pattern that has previously been accessed via a multi-step synthesis. We demonstrate a simple one-pot preparation of 1-lithiodibenzothiophene from commercial materials via a cascade of two benzyne additions and conversion to several derivatives by addition of electrophiles. A chiral amine containing the 1-dibenzothiophene motif was also prepared. This work avoids the use of precious metals or tert-butyllithium and is much shorter and more convenient than existing routes to 1-substituted dibenzothiophenes.

The Suzuki–Miyaura reaction of BPin-substituted F-BODIPYs with aryl halides

F-BODIPYs substituted with BPin functionality have been coupled to aryl halides using a mild and efficient catalyst system involving Pd2(dba)3 and XPhos. The methodology enables the Suzuki–Miyaura cross-coupling of electron-rich, electron-poor, and sterically encumbered BPin-substituted F-BODIPYs to aryl halides bearing various functional groups, thus presenting an opportunity for the preparation of highly functionalised F-BODIPYs without need for the corresponding aryl moiety to be available in borylated form.

Fabrication of Pd NPs on pectin-modified Fe3O4 NPs: A magnetically retrievable nanocatalyst for efficient C-C and C-N cross coupling reactions and an investigation of its cardiovascular protective effects

The present report represents the synthesis of a novel Pd NPs immobilized over a natural polysaccharide (pectin) coated Fe₃O₄ magnetic nanocomposite material (Fe₃O₄@pectin/Pd) for investigating the cardiovascular protective effects. The biomolecular functionalization not only stabilizes the ferrite nanoparticles from agglomeration but also provides an environment for the biogenic reduction of Pd²⁺ ions. This protocol is a promising breakthrough for the synthesis of a quasi-heterogeneous catalyst, a bridge between heterogeneous and homogeneous medium. The structure, morphology and physicochemical properties of the material were characterized utilizing various analytical techniques like FT-IR, FE-SEM, TEM, VSM, EDX-elemental mapping, ICP, EDX and XPS. The catalyst showed excellent reactivity in C-C and C-N cross coupling reactions via Suzuki and Buchwald-Hartwig reactions respectively. An array of different biphenyls and aryl amines were then procured by reactions of various aryl halides with phenylboronic acid or secondary amines over the catalyst affording good to excellent yields. The catalyst was easily recoverable using an external magnet and thereafter recycled for several trials with insignificant palladium leaching or loss in catalytic performance. To investigate the cardiovascular protective activities of catalyst, the MTT assay was done on Human Aortic Endothelial Cells (HAEC), Human Coronary Artery Endothelial Cells (HCAEC), and Human Pulmonary Artery Endothelial Cells (HPAEC) cell lines. Nanocatalyst-treated cell cutlers significantly (p ≤ 0.01) decreased the caspase-3 activity, and DNA fragmentation. It raised the cell viability and mitochondrial membrane potential in the high concentration of Mitoxantrone-treated HAEC, HCAEC, and HPAEC cells. According to the above findings, nanocatalyst can be administrated as a cardiovascular protective drug for the treatment of cardiovascular diseases after approving in the clinical trial studies in humans.

3D designed and printed chemical generators for on demand reagent synthesis

Modern science has developed well-defined and versatile sets of chemicals to perform many specific tasks, yet the diversity of these reagents is so large that it can be impractical for any one lab to stock everything they might need. At the same time, isssues of stability or limited supply mean these chemicals can be very expensive to purchase from specialist retailers. Here, we address this problem by developing a cartridge -oriented approach to reactionware-based chemical generators which can easily and reliably produce specific reagents from low-cost precursors, requiring minimal expertise and time to operate, potentially in low infrastructure environments. We developed these chemical generators for four specific targets; transition metal catalyst precursor tris(dibenzylideneacetone)dipalladium(0) [Pd₂(dba)₃], oxidising agent Dess-Martin periodinane (DMP), protein photolinking reagent succinimidyl 4,4’-azipentanoate (NHS-diazirine), and the polyoxometalate cluster {P₈W₄₈}. The cartridge synthesis of these materials provides high-quality target compounds in good yields which are suitable for subsequent utilization.

Synthetic labs rely on a vast number of chemicals, which are often unstable with time and affected by price fluctuations. Here, the authors report ad hoc developed cartridge reactionware for the synthesis of four different targets in a time- and cost-saving manner.

Synthesis of biaryls using aryne intermediates

The synthesis of biaryls from benzyne intermediates offers an alternative strategy to conventional metal-catalyzed cross-coupling approaches.

Palladium NPs supported on novel imino-pyridine-functionalized MWCNTs: efficient and highly reusable catalysts for the Suzuki–Miyaura and Sonogashira coupling reactions

In this article a new heterogeneous nanocatalyst based on palladium supported on functionalized multi-walled carbon nanotubes (MWCNTs) has been introduced.

Double heteroatom functionalization of arenes using benzyne three-component coupling

Arynes participate in three-component coupling reactions with N, S, P, and Se functionalities to yield 1,2-heteroatom-difunctionalized arenes. Using 2-iodophenyl arylsulfonates as benzyne precursors, we could effectively add magnesiated S-, Se-, and N-nucleophilic components to the strained triple bond. In the same pot, addition of electrophilic N, S, or P reagents and a copper(I) catalyst trapped the intermediate aryl Grignard to produce a variety of 1,2-difunctionalized arenes.

An efficient and reusable catalyst for Suzuki cross-coupling reactions in aqueous solution—hollow palladium–ferrum bimetallic magnetic spheres

Hollow Pd–Fe bimetallic magnetic spheres are synthesized in this work.

Platinum(0) olefin complexes of a bulky terphenylphosphine ligand. Synthetic, structural and reactivity studies

A novel terphenylphosphine PMe₂Ar^Dipp2 (1) (Dipp = 2,6-ⁱPr₂C₆H₃) forms stable Pt(0) complexes with ethene and 3,3-dimethylbut-1-ene that behave as sources of the reactive Pt(PMe₂Ar^Dipp2) fragment.

Palladium-catalyzed cross-coupling of benzyl chlorides with cyclopropanol-derived ketone homoenolates

The palladium-catalyzed cross-coupling reaction of cyclopropanol-derived ketone homoenolates with benzyl chlorides is reported. This reaction proceeds in high yields with electron-neutral and electron-rich benzyl chlorides; however, yields are low with electron-poor benzyl chlorides. In addition, a range of cyclopropanols can be coupled in good yields. The reaction can be conducted with a low catalyst loading (1% Pd) and on a gram scale without reduction in yield.