A New Model of Inductive Effect in the Analysis of Organophosphorus Reactivity

Abstract

Structure and reactivity correlation is one of the most important problems of modern organic and organoelement chemistry.     

Radical reactions of highly polar molecules. Chlorination of halopropanes

In polychloro-2,2-difluoropropanes, where a large inductive effect results in relatively low reactivity to chlorination, the presence of additional chlorine causes an increased reactivity of the hydrogens geminal to the chlorine and a reduced reactivity of the remote (third carbon) hydrogens. The ways in which resonance, inductive effect, and steric crowding interact in the rates of chlorination of polar molecules are discussed.     

Modern Approaches to the Synthesis and Transformations of Practically Valuable Benzothiazole Derivatives

The review is devoted to modern trends in the chemistry of 2-amino and 2-mercapto substituted benzothiazoles covering the literature since 2015. The reviewed heterocycles belong to biologically active and industrially demanded compounds. Newly developed synthesis methods can be divided into conventional multistep processes and one-pot, atom economy procedures, realized using green chemistry principles and simple reagents. The easy functionalization of the 2-NH₂ and 2-SH groups and the benzene ring of the benzothiazole moiety allows considering them as highly reactive building blocks for organic and organoelement synthesis, including the synthesis of pharmacologically active heterocycles. The review provides a summary of findings, which may be useful for developing new drugs and materials and new synthetic approaches and patterns of reactivity.     

Synthese neuer organoelementsubstituierter pentadiene (1)

By applying four different methods twelve new organoelement substituted pentadienes have been prepared. They contain one or two organoelement groups. - Pentadienyllithium (2) reacted with Cl-SPh, Br-SePh, Cl-PPh₂, and Cl-AsPh₂ (lone pair at the element) exclusively to the corresponding E-1-(organoelement)-2,4-pentadiene, whereas with Cl-MMe₃ (M = Si, Ge, Sn) (2,3,4), Cl-GePh₃, and Cl-SnPh₃ (no lone pair at the element) a mixture of the E- and Z-1-(organoelement)-2,4-pentadiene is formed. An interpretation of this different behaviour is given.     

Propargyl‐Assisted Selective Amidation Applied in C‐terminal Glycine Peptide Conjugation

Alkyl esters, such as propargyl esters, typically lack the electron‐withdrawing inductive effects needed to participate in nucleophilic acyl substitution reactions. Herein, we report an unusual observation in which glycine propargyl ester derivatives displayed selective, base‐independent reactivity towards linear alkylamines under mild, metal‐free conditions. Through global reaction route mapping (GRRM) modeling calculations, it is predicted that these observations may be governed by factors related to hydrogen‐bonding and intermolecular interactions, rather than electron‐withdrawing inductive effects. Based on this concept of propargyl‐assisted selective amidation, a direct application was made to develop a novel site‐specific C‐terminal glycine peptide bioconjugation technique as a proof‐of‐concept, which relies upon the selective reactivity of glycine propargyl esters over that of aspartate and glutamate side‐chain‐linked propargyl esters.     

Chemistry of 1,2-diphospholide anions and 1,2-diphospholes

The main trends in the chemistry of 1,2-diphosphacyclopentadienes (1,2-diphospholes) and their derivatives 1,2-diphosphacyclopentadienide anions (1,2-diphospholide anions) were systematized, analyzed, and generalized. Methods for the generation of 1,2-diphospholide anions and their reactions with organic and organoelement electrophiles, as well as with transition metal complexes, were considered. Particular attention was paid to the cycloaddition reactions of 1-alkyl-1,2-diphospholes to obtain polycyclic chiral phosphines. A comparative analysis of the reactivity of 1,2-diphospholes and 1,2-diphospholide anions with respect to other representatives of phosphacyclopentadienes and phosphacyclopentadienide anions was carried out. The potential of application of 1,2-diphosphacyclopentadiene derivatives for the design of materials with magnetic, catalytic, and optical properties was shown.

     

New Possible Applications of Heavy Main-Group Elements in Organic Synthesis

Aside from elements of the 2nd row, and one element of the 3rd row of the periodic system—Si, P, S, and Se, respectively, whose organoelement groups such as Me₃Si and Ph₃P^⊕ have proven useful in numerous organic syntheses—other elements of the 3rd as well as 4th and 5th row (Ge, As, Sn, Sb, Te, Pb, Bi) can also be used as components of synthetically useful organoelement groups, the elements As, Sn, and Pb, in particular, offering certain advntages over the others. Some of these organoelement groups are suitable equivalents for Li- or halogen-substituents attached to carbon; they stabilize carbanionic centers (minimum of this effect at the 3rd-row elements), and owing to their suitability as leaving groups in β-eliminations, also open up interesting synthetic possibilities. The thermally unduced syn- and silica-gel induced anti-elimination of Ph₃Sn, Ph₂Sb, Ph₃Pb, together with β-OH, are novel. With the newly synthesized compounds Ph_nEl—Ch₂—Li (El = Sn, Pb, As, Sb, Bi) and other α- and β-lithiated R_nEl- and Ph₂As(O)-reagents such organoelement groups can be introduced into organic compounds and exploited in organic and organoelement synthesis.     

Thermal oxidative stability of yttrium containing oligomeric silazanes with organoelement substituents and multiceramics on their basis

Russian Chemical Bulletin - Characteristics of thermal transformations of oligomeric silazanes with organoelement substituents at the N atoms (M-OESs) containing one element M = Y, Zr, or Hf or a...     

Deep purification of hexamethyldisilazane

We considered a deep cleaning of 1,1,1,3,3,3-hexamethyldisilazane used in microelectronics and organoelement synthesis from a series of homogeneous and heterogeneous admixtures by various physicochemical methods.     

The Synthesis,Structure and Properties of Phosphire-Nium Halogenides

Abstract

In the study of electrophilic addition of organoelement halogenides to alkoxyacetylensl it has been found that in the absence of catalysts dialkyl(pheny1)halogenphosphines add to internal alkoxyacetylenes, which results in the formation of stable phosphirenes (I) of a new type.     

Die Reaktion des Digalliumsubiodids R(I)Ga‐Ga(I)R [R = C(SiMe3)3] mit Lithium‐diphenylphosphanid – radikalische Öffnung der Ga‐Ga‐Bindung

The Reaction of the Digallium Subiodide R(I)Ga‐Ga(I)R [R = C(SiMe₃)₃] with Lithium Diphenylphosphanide – Radical Cleavage of the Ga‐Ga Bond The easily available organoelement digallium(II) subiodide R(I)Ga‐Ga(I)R ( 1 ) [R = C(SiMe₃)₃] reacted with two equivalents of lithium diphenylphosphanide in toluene by the replacement of both iodine atoms by two phosphanido groups. The product, [R(H)Ga‐P(C₆H₅)₂]₂ ( 2 ), contains a four‐membered Ga₂P₂ heterocycle without direct Ga‐Ga bonding interactions and the gallium atoms exclusively in an oxidation state of +III. They are attached to hydrogen atoms, which may result from a reaction of a reactive intermediate with the solvent.     

Mesophase structure and some properties of liquid-crystalline organoelement polymers

The structure and physico-mechanical properties of polyphosphazene, poly(trimethylvinylsilane) and blends of polyphosphazene with polyethylene were studied. It was shown that these organoelement homopolymers form mesophase structure which can be described as condis-crystal, and mesophase polymers are effective modifiers when mixed as blends with polyethylene, allowing to make processing more effective and obtain composites with improved mechanical properties.     

A comment on the reactivity of methoxymethyl (mom) and β-methoxyethoxymethyl (mem) esters.

A cumulative negative inductive effect, not internal chelation of metal ions, is invoked to explain the enhanced reactivity of MEM and MOM esters.     

New Sulfur,Silicon and Phosphorus Containing Reagents

The problems of synthesis and transformations of new organoelement reagents containing sulfur, silicon and phosphorus (S-P-O-Si, P(S)-S-Si) are discussed.     

Zeolite Modification with Aluminum and Efficiency of Gas Purification

A method for modifying the NaX zeolite with aluminum via decomposition of an organoelement compound at low temperature was developed. The basic parameters of gas purification with the modified zeolite were determined.     

超共轭效应对有机化合物结构和反应性的影响

超共轭效应是基础有机化学教学中的一个重要知识点,是基团诱导效应和共轭效应的补充和发展。本文通过基础有机化学教学中的常见实例,分析和阐述了多种超共轭效应对有机化合物及中间体结构稳定性和相对反应性的贡献。     

Preparation of Transformer Oil Body by Extraction Refining of 300-500°C Fraction of Low-Paraffinicity Oil

A raffinate meeting the requirements for the transformer oil body was obtained from the 300-350°C fraction of low-paraffinicity oil by five-step countercurrent extraction of aromatic hydrocarbons and organoelement compounds with aqueous methyl Cellosolve in the presence of pentane.     

Extraction Refining of Heavy Vacuum Gas Oil

Selective refining of heavy vacuum gas oil and a combined fraction of light and heavy vacuum gas oils to remove aromatic and organoelement compounds and heavy metals by five-step countercurrent extraction with N-methylpyrrolidone or dimethylacetamide in the presence of heptane containing 1 wt % toluene was studied.     

Electrochemistry of Organophosphorus Compounds

Progress in electrochemistry of organophosphorus compounds is rewieved. Mechanisms of oxidation and reduction reactions under the conditions of homogenous electrocatalysis and possibility of use the primary compounds for the synthesis of various organic and organoelement compounds are considered.     

From the discovery of sodiumoxyorganoalkoxysilanes to the organosilicon dendrimers and back

Upon being discovered 20 years ago, sodiumoxyorganoalkoxysilanes became the key to the world of organoelement dendrimers. Even considering the great variety of objects that had appeared in this area during the last 20 years, the organosilicon dendrimers are still one of the most actual objects in this class. Above all, this is fair concerning the carbosilane systems. The high reactivity of the functional groups, the well controlled chemistry of their transformations, and the inertness of the molecular skeleton are the reason for making these systems highly actual in two main regards: as model objects for the deep research of the dendrimers' properties and as polyfunctional matrixes for numerous derivatives. In this review, we were mainly focusing on the importance of the former part. In the conclusion, we showed the motivation for further development of this area both in regard of synthesis of new carbosilane systems and further development of siloxane dendrimers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4935–4948, 2008