有机磷试剂在不对称反应中的应用

由于其结构多样性,有机磷化合物作为配体、催化剂、辅助剂、添加剂、底物以及试剂等在不对称反应中均获得了成功的应用,从而使有机磷试剂在不对称反应研究领域占有举足轻重的地位.本文全面介绍了本课题组近几年来围绕有机磷试剂在不对称反应中的应用,在醛的不对称硅氰化反应、内消旋环氧烷不对称开环反应、潜手性酮的不对称硼烷还原、不对称Friedel-Crafts烷基化、对映选择Mitsunobu、不对称aza-Morita-Baylis-Hillman、不对称aza-Henry以及硝基烯的不对称Michael加成反应等方面所取得的一些研究结果.     

离子交换—电感耦合等离子体发射光谱法测定石灰石中的微量磷

本文介绍一种用ICP-AES法测定难熔材料石灰石中微量磷的方法。样品用HF-HNO_3-HCIO_4混合酸分解后,用阳离子交换树脂分离除去共存的金属离子,含磷溶液经浓缩后用ICP-AES法进行测定。本法用于测定含磷量为数十微克/毫升的石灰石样品,平行测得结果的相对标准偏差在2～3％之间,加入回收率为96～102％。     

磷单质概念的新发展

自白磷与红磷相继被发现后，磷单质的概念初步形成。20世纪初期，黑磷的发现突破了人们对磷单质的认识。随后，紫磷、蓝磷、二磷分子以及环状磷的出现，使磷单质的概念有了新的发展。几种新的磷单质的发现，建立了磷单质概念的新范式，科学家在探索磷单质概念多元化的道路上还将继续前行。     

3‐Bromo‐2‐Pyrone: An Alternative and Convenient Route to Functionalized Phosphinines

The facile access to 3‐bromo‐2‐pyrone allows the preparation of 6‐bromo‐2‐trimethylsilyl‐phosphinine by a [4+2] cycloaddition with Me₃Si‐C≡P for the first time. The regioselectivity of this reaction could be verified by means of single crystal X‐ray diffraction of the corresponding W⁰ complex. In the presence of ZnBr₂ and dppp (1,3‐bis(diphenylphosphino)propane) as a bidentate ligand, the bromo‐phosphinine quantitatively undergoes a Negishi cross‐coupling reaction with PhLi that selectively leads to 6‐phenyl‐2‐trimethylsilyl‐phosphinine. This heterocycle could again be characterized by means of X‐ray diffraction as a W⁰ complex. These results describe a new and convenient route to 2,6‐disubstituted phosphinines that makes use of readily available starting materials.     

Stabilization of Black Phosphorus by Sonication-Assisted Simultaneous Exfoliation and Functionalization

Black phosphorus (BP) has extraordinary properties, but its ambient instability remains a critical challenge. Functionalization has been employed to overcome the sensitivity of BP to ambient conditions while preserving its properties. Herein, a simultaneous exfoliation–functionalization process is reported that functionalizes BP flakes during exfoliation and thus provides increased protection, which can be attributed to minimal exposure of the flakes to ambient oxygen and water. A tetrabutylammonium salt was employed for intercalation of BP, resulting in the formation of flakes with large lateral dimensions. The addition of an aryl iodide or an aryl iodonium salt to the exfoliation solvent creates a scalable strategy for the production of functionalized few-layer BP flakes. The ambient stability of functionalized BP was prolonged to a period of one week, as revealed by STEM, AFM, and X-ray photoelectron spectroscopy.     

Stereochemical Behavior of Pairs of P-stereogenic Phosphanyl Groups at the Dimethylxanthene Backbone

The P-stereogenic bis(phosphanes) 7 and 9 , featuring pairs of P(Mes)-ethynyl or vinyl substituents at the dimethyl xanthene backbone show rather low barriers of stereochemical inversion at phosphorus. π-Conjugative effects are probably causing these low inversion barriers. Compound 7 reacted with B(C₆F₅)₃ to form the nine-membered heterocyclic product 10 , featuring a [P]−C≡C−B(C₆F₅)₃ substituent. Compound 7 was converted to the bis[P(Mes)vinyl] xanthene derivative 9 , which gave the zwitterionic P(H)(Mes)−CH=CH−B(C₆F₅)₃ containing product 16 upon treatment with B(C₆F₅)₃. Thermally induced epimerization barriers at phosphorus of ca. 20 to 27 kcal mol⁻¹ were calculated by DFT for the alkenyl- and alkynyl-P derived systems 6 to 9 , 15 and 16 and experimentally determined for the examples 7 and 16 .     

New Condensed Heterocyclic System with a Bridgehead Phosphorus Atom

New condensed heterocyclic system with a bridgehead phosphorus atom has been synthesized by the reaction of imidazolyl anilides of 3,4-dimethoxy- and 3-dimethylaminobenzoic acids with phosphorus(III) halides. The reaction begins with the formation of cyclic halogenophosphonites which are later able to undergo intramolecular heterocyclization to form pentacyclic compounds.     

Electrochemical synthesis of phosphorus esters from white phosphorus in the presence of copper complexes and ethanol

In the presence of white phosphorus the redox potentials of the copper ions change and the potential of the reduction wave of Cu^I/Cu⁰ shifts noticeably toward more positive values. The Cu^I—P₄ complex is characterized by a lower value of the electrochemical gap, that is, higher polarizability and reactivity compared to those of the free Cu^I cation. Phosphorus esters can be synthesized from P₄ and ethanol. The latter is in the composition of the copper(ii) complexes, which act as a catalyst-charge mediator.     

超声波溶样法快速测定磷酸二铵中的水溶性磷和有效磷

建立了超声波溶样快速测定磷酸二铵中的水溶性磷和有效磷的方法。采用正交试验法分析影响溶解效果的因素，确定了最佳的溶解条件。溶样时间从8－12h缩短到30min。该方法简便、快捷，与经典法对照，精密度和准确度无显著性差异。     

Phosphorus and Its Water-Extractable Inorganic Form in Medicinal Herb Infusions

Abstract

The concentration of total phosphorus (P), its water-extractable inorganic form (P-PO₄), and Mg, Mn, Cu, Zn, and Fe, was established in 57 samples of Polish medicinal herbs originating from 6 plant species—Mentha piperita, Urtica dioica, Salvia officinalis, Melissa officinalis, Tussilago farfara, and Betula sp. Total P, P-PO₄, and Mg were determined at average levels of mg/g, whereas the other elements were at mg/kg of dry plant weight. A higher level of P and P-PO₄ was detected in Menthae piperitae folium and Salviae folium—plants of the same Labiatae family. With the other elements, an extremely high level of total Mn and Zn was found in Betulae folium. Analysis of relations between P, P-PO₄, and the essential elements in the study showed that an especially strong inter-relation occurred in the pairs: P and P-PO₄, P-PO₄ and Mg, Mn and Zn, both between their total concentrations and extractable forms. This would indicate synergistic activity on the part of these elements in the physiology of plants.

GRAPHICAL ABSTRACT      

Functionalization of P4 Using a Lewis Acid Stabilized Bicyclo[1.1.0]tetraphosphabutane Anion

Reacting white phosphorus (P₄) with sterically encumbered aryl lithium reagents (aryl=2,6‐dimesitylphenyl or 2,4,6‐tBu₃C₆H₂) and B(C₆F₅)₃ gives the unique, isolable Lewis acid stabilized bicyclo[1.1.0]tetraphosphabutane anion. Subsequent alkylation of the nucleophilic site of the RP₄ anion gives access to non‐symmetrical disubstituted bicyclic tetraphosphorus compounds. This novel method enables P? C bond formation in a controlled fashion using white phosphorus as starting material.