Stereochemistry of electrophilic and nucleophilic substitutions at phosphorus

2019 ◽  
Vol 91 (1) ◽  
pp. 43-57 ◽  
Author(s):  
Oleg I. Kolodiazhnyi
Keyword(s):  
Nucleophilic Substitution ◽  
Absolute Configuration ◽  
Electrophilic Substitution ◽  
Thermodynamic Control ◽  
Nucleophilic Substitutions ◽  
Electrophilic Substitutions ◽  
Organophosphorus Chemistry

Abstract Nucleophilic and electrophilic substitutions are the most often applied reactions in organophosphorus chemistry. They are closely interrelated, because in a reacting pair always one reagent is an electrophile, and another nucleophile. The reactions of electrophilic and nucleophilic substitutions at the phosphorus center proceed via the formation of a pentacoordinated intermediate. The mechanism of nucleophilic substitution involves the exchange of ligands in the pentacoordinate phosphorane intermediate, leading to the more stable stereomer under the thermodynamic control. Electrophilic substitution proceeds with retention of absolute configuration, whereas nucleophilic substitution with inversion of configuration at the phosphorus center.

scholarly journals Asymmetric Electrophilic Reactions in Phosphorus Chemistry

Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 108 ◽  
Author(s):  
Anastasy O. Kolodiazhna ◽  
Oleg I. Kolodiazhnyi
Keyword(s):  
Absolute Configuration ◽  
Electrophilic Substitution ◽  
Organophosphorus Compounds ◽  
Phosphoryl Group ◽  
Substitution Reactions ◽  
Molecular Chemistry ◽  
Electrophilic Reactions ◽  
Wide Range ◽  
Further Development ◽  
Organophosphorus Chemistry

This review is devoted to the theoretic and synthetic aspects of asymmetric electrophilic substitution reactions at the stereogenic phosphorus center. The stereochemistry and mechanisms of electrophilic reactions are discussed—the substitution, addition and addition-elimination of many important reactions. The reactions of bimolecular electrophilic substitution SE2(P) proceed stereospecifically with the retention of absolute configuration at the phosphorus center, in contrast to the reactions of bimolecular nucleophilic substitution SN2(P), proceeding with inversion of absolute configuration. This conclusion was made based on stereochemical analysis of a wide range of trivalent phosphorus reactions with typical electrophiles and investigation of examples of a sizeable number of diverse compounds. The combination of stereospecific electrophilic reactions and stereoselective nucleophilic reactions is useful and promising for the further development of organophosphorus chemistry. The study of phosphoryl group transfer reactions is important for biological and molecular chemistry, as well as in studying mechanisms of chemical processes involving organophosphorus compounds. New versions of asymmetric electrophilic reactions applicable for the synthesis of enantiopure P-chiral secondary and tertiary phosphines are discussed.

Organic Reactivity in Ionic Liquids: Some Mechanistic Insights into Nucleophilic Substitution Reactions

2005 ◽  
Vol 2005 (7) ◽  
pp. 413-417 ◽  
Author(s):  
N. Llewellyn Lancaster
Keyword(s):  
Ionic Liquids ◽  
Nucleophilic Substitution ◽  
Organic Reactions ◽  
Substitution Reactions ◽  
Nucleophilic Substitutions ◽  
Nucleophilic Substitution Reactions ◽  
Quantitative Studies ◽  
Alternative Solvents ◽  
Molecular Solvents ◽  
Organic Reactivity

Ionic liquids have been advanced as alternative solvents for organic reactions. In this paper, the principal findings of studies on nucleophilic substitutions in ionic liquids are reviewed. Thus our examination of halides (Cl-, Br- and I) in a range of ionic liquids is combined with our study of amine nucleophilicity into a single narrative. There have been a few other quantitative studies of nucleophilic substitutions in ionic liquids, and the results of these studies are also summarised in this work. These data are compared to related reactions in molecular solvents, and used to show where ionic liquids do (and do not) offer advantages over molecular solvents for nucleophilic substitutions.

Kinetics of the chlorination of azobenzene and comparison with azoxybenzene

1984 ◽  
Vol 37 (11) ◽  
pp. 2249
Author(s):  
KA Ahmed ◽  
PJ Hanhela ◽  
M Hassan ◽  
J Miller ◽  
DB Paul
Keyword(s):  
Nucleophilic Substitution ◽  
Kinetic Data ◽  
Electrophilic Substitution ◽  
Relative Rate ◽  
Molecular Chlorine ◽  
Partial Rate ◽  
Reaction Proceeds ◽  
Kinetics Of ◽  
No Activation

The activating effect of the phenylazo substituent in electrophilic substitution has been examined. The rates and partial rate factors for chlorination of azobenzene with molecular chlorine and protonated chlorine acetate have been determined relative to benzene. Whereas the chlorine acetate reaction proceeds readily (relative rate 4900) there is virtually no activation to chlorination by molecular chlorine. Complexes between azobenzene and bromine were, however, isolated and chatacterized. Their formation implies that during molecular halogenation reactions the electrophile is essentially unavailable. The relative chlorination rates for azobenzene and azoxybenzene have also been established: the phenylazo group is more activating towards protonated chlorine acetate whereas azoxybenzene (which does not complex with halogens) is the more reactive with molecular chlorine. The chlorination results confirm the versatility of the phenylazo group which is the first substituent for which kinetic data have been obtained quantifying activation of aromatic electrophilic, radical and nucleophilic substitution.

Dearomatisation of 2-naphthol by oxidative nucleophilic substitution and oxidative electrophilic substitution

1984 ◽  
pp. 2069-2076 ◽  
Author(s):  
Humberto Arzeno ◽  
Derek H. R. Barton ◽  
Reine-Marie Bergé-Lurion ◽  
Xavier Lusinchi ◽  
B. Mario Pinto
Keyword(s):  
Nucleophilic Substitution ◽  
Electrophilic Substitution

Synthesis of aromatic functionalized cage-rearranged silsesquioxanes (T8, T10, and T12) via nucleophilic substitution reactions

2015 ◽  
Vol 44 (3) ◽  
pp. 916-919 ◽  
Author(s):  
Supansa Chimjarn ◽  
Rungthip Kunthom ◽  
Prapassorn Chancharone ◽  
Rapheepraew Sodkhomkhum ◽  
Preeyanuch Sangtrirutnugul ◽  
...  
Keyword(s):  
Nucleophilic Substitution ◽  
Building Blocks ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Substitution Reactions ◽  
Nucleophilic Substitutions ◽  
Inorganic Hybrid ◽  
Nucleophilic Substitution Reactions

Organic–inorganic hybrid nano-building blocks of aryl nitro-, aldehyde-, and bromo-functionalized polyhedral oligomeric silsesquioxanes (T8, T10, and T12) were easily prepared through nucleophilic substitutions.

ρ as a quantitative measure of transition state structure

1979 ◽  
Vol 57 (3) ◽  
pp. 255-257 ◽  
Author(s):  
Bo-Long Poh
Keyword(s):  
Free Radicals ◽  
Hydrogen Atom ◽  
Transition State ◽  
Nucleophilic Substitution ◽  
Electrophilic Substitution ◽  
Quantitative Measure ◽  
Hydrogen Atom Abstraction ◽  
State Structure ◽  
Transition State Structure ◽  
Substitution Reactions

The values of the Brønsted exponent for several examples of nucleophilic substitution reactions, aromatic electrophilic substitution reactions, and hydrogen atom abstraction from toluene by free radicals have been calculated from the ρ values of the corresponding reactions. The magnitude of the Brønsted exponent is shown to indicate the degree of charge developed in the transition state structure.

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