Description: 1. Current Aspects of the Solution Chemistry of Arylnitrenes.- I. Introduction.- 1. Definition and Historical.- 2. Nomenclature.- 3. Methods of Generation and Evidence for Arylnitrenes.- A. Thermolysis of Aryl Azides.- B. Photolysis of Aryl Azides.- C. Reduction of Nitro and Nitrosoarenes.- D. Fragmentation of Heterocycles.- E. Oxidation of Amines.- F. Newer Methods of Generation.- 4. Spectral, Structural, and Theoretical Considerations.- II. Intermodular Reactions.- 1. Singlet Reactions.- A. Aromatic Substitution.- B. Addition to Alkenes.- C. Reactions with Nitriles.- D. Trapping by Carbon Monoxide.- E. Electrophilic Substitution at Nitrogen.- 2. Triplet Reactions.- A. Aniline Formation.- B. "Dimerization".- C. Insertion into Aliphatic C-H Bonds.- D. Reaction with Nitrosoarenes.- E. Reaction with Oxygen.- F. Substitution of a Carbon-Fluorine Bond.- 3. "Benzazirine" Reactions.- A. With Nucleophiles.- B. With Electrophiles.- III. Intramolecular Reactions.- 1. Nitrene-Induced Cyclizations.- A. To form Five-Membered Rings.- B. Closure to Six-Membered Rings.- 2. Heterocyclic Rearrangements.- IV. Decomposition in the Presence of Protonic and Lewis Acids.- V. Current and Future Application.- References.- 2. Nitrile Ylides and Nitrenes From 2H-Azirines.- I. Generation of Nitrile Ylides.- II. Features of the Photocycloaddition Reaction of 2H-Azirines.- III. Photochemical Dimerizations of 2H-Azirines.- IV. Intramolecular 1,5-Electrocyclization Reactions of Vinyl Substituted 2H-Azirines.- V. Properties of Nitrile Ylides.- VI. Intramolecular Photocycloaddition Reactions of 2H -Azirines.- VII. Further Reactions of 2H-Azirines.- VIII. Thermal Reactions of2H-Azirines.- References.- 3. Radical Cyclizations by Intramolecular Additions.- I. Introduction.- II. General Presentation: The Early Results.- 1. The Unstabilized 5-Hexenyl Radicals.- 2. The Stabilized 5-Hexenyl Radicals.- III. Attempts to Rationalize the Selectivities Observed in the Cyclization of 5-Hexenyl Radicals.- 1. The Irreversible Pathway: Why Is the (Cy''5) Radical Favored'.- A. The Steric Hypothesis.- B. The Stereoelectronic Hypothesis.- C. The Entropic Hypothesis.- D. Conclusion.- 2. The Reversible Pathway Favoring the (Cy''6) Radical.- IV. Alkyl Substituted 5-Hexenyl Radicals.- V. Alkenyl Radicals Other than 5-Hexenyl.- 1. The Higher Homologs.- 2. The Lower Homologs.- A. The 4-Pentenyl Radicals.- B. The 3-Butenyl Radicals.- C. The Allyl Radical.- 3. Conclusion.- VI. Carbon-Centered Alkenyl Radicals Containing Heteroatoms.- 1. Introduction.- 2. Unsaturated Radicals Bearing a Heteroatom in the Chain.- 3. Diallylic Substrates.- 4. Unsaturated Radicals Bearing Fluorine Atoms on the Chain.- VII. Alkenyl Radicals Bearing Stabilizing Groups on the Carbon Radical Center.- 1. Introduction.- 2. The 5-Hexenyl-and 5-Hexenylalkyl-Substituted Radicals.- 3. Other Alkenyl Radicals.- 4. The Stabilizing Groups.- 5. Conclusion.- VIII. Heteroatom-Centered Radicals.- 1. Introduction.- 2. Oxygen-Centered Radicals.- A. Alkoxyl Radicals.- B. Aryloxyl Radicals.- C. Acyloxyl Radicals.- D. Peroxyl Radicals.- 3. Nitrogen-Centered Radicals.- A. Aminyl Radicals.- B. Arylaminyl Radicals.- C. Amidyl Radicals.- D. Nitroxide Radicals.- 4. Sulfur-Centered Radicals.- A. Unsaturated Thiyl Radicals Generated from Unsaturated Mercaptans.- B. Unsaturated Thiyl Radicals Generated from Unsaturated Sulfides or Disulfides.- C. Enethiyl-Unsaturated Radicals, Arylthiyl-Unsaturated Radicals and the Thio-Claisen Rearrangement.- 5. Other Heteroatom-Centered Radicals.- A. Phosphorus-Centered Radicals.- B. Silicon-Centered Radicals.- C. Germanium-Centered Radicals.- D. Tin-Centered Radicals.- E. Selenium-Centered Radicals.- 6. Conclusion.- IX. Intramolecular Addition to Other Carbon-Carbon Bonds.- 1. Introduction.- 2. Intramolecular Addition to Acetylenic Bonds of Carbon-Centered Radicals.- 3. Intramolecular Addition of Heteroatomic Radicals to Acetylenic Bonds.- 4. Intramolecular Addition to Allenes and Cyclopropanes.- X. Intramolecular Addition to Polar Multiple Bonds Such as Carbonyl or Cyano.- 1. Intramolecular Addition to the Carbonyl Bond.- A. The ?-Scission Process.- B. The Intramolecular Addition.- C. Conclusion.- 2. Intramolecular Addition to Carboxylic Acids and Esters.- 3. Intramolecular Addition to the Cyano Group.- 4. Intramolecular Addition to Other Polar Bonds.- A. The C=S Bond.- B. The C=N-Bond.- C. The-N=N-Bond.- D. The Nitroso and Nitrone Groups.- E. The Nitro Group.- F. The Azido Group.- G. The Sulfone Group.- 5. Conclusion.- XI. Synthesis of Bi- and Poly cyclic Compounds. Stereochemical Features of Free Radical Intramolecular Additions.- 1. Introduction.- 2. Bicyclic Compounds.- A. The Cy5/Cy6 Case.- B. The Cy6/Cy7 Case.- C. The Cy4/Cy5 Case.- D. The Cy3/Cy4 Case.- E. The Allyl Radical.- 3. Stereochemical Features of Free Radical Intramolecular Addition.- 4. Polycyclization Reactions.- A. Carbon-Centered Radicals.- B. Heteroatom-Centered Radicals.- C. Polycyclization Reactions Involving Addition to a Polar Bond.- 5. Conclusion.- XII. Free Radical Intramolecular Addition as a Mechanistic Tool and a Kinetic Standard.- 1. The Mechanistic Tool.- A. The 5-Hexenyl Radical.- B. Other Carbon-Centered Radicals.- C. Heteroatomic Radicals.- D. Reactions Related to Free Radical Intramolecular Additions.- E. Comments on the Use of Unsaturated Systems Cyclization as a Free Radical Proof.- 2. The Kinetic Standard.- XIII. Conclusion.- References.- 4. Reactions of Silicon Atoms and Silylenes.- I. Introduction.- II. Methods of Generation of Silicon Atoms.- 1. Nuclear Recoil Method.- 2. Thermal Evaporation Method.- III. Reaction Modes of Silicon Atoms.- 1. Si-H Bond Insertion.- 2. Apparent H Abstraction.- 3. Apparent F Abstraction.- 4. Possible Si-Si Bond Insertion.- 5. Apparent 1,4 Addition to Dienes.- 6. Reactions of Silicon with SiX4 and Other Halides.- 7. Reactions of Si Species from (n, ?) Reactions.- IV. Modes of Formation of Silylenes.- 1. Derived from Si Atoms and Elemental Silicon.- A. Si Atom Abstraction--the Nuclear Recoil Method.- B. Si Atom Insertion--the Co-Condensation Method.- C. Disproportionate Involving Silicon--the High-Temperature Reaction Method.- D. Abstraction from Single-Crystal Silicon--the Molecular Beam Method.- 2. The Decomposition Method.- A. From Monosilanes.- B. From Disilanes.- C. From Trisilanes.- D. From Polysilanes.- E. From Silacyclopropanes.- F. From 7-Silanorbornadienes.- G. From Metal Silyls.- 3. The Reduction Method.- A. Reduction with H2.- B. Reduction with Metallic Elements.- V. Spectroscopic and Thermodynamic Properties of Silylenes.- 1. Electronic States.- A. Ground Electronic States of Silylenes.- B. Electronic States of Reacting Silylenes.- 2. Structure.- 3. Heats of Formation.- VI. Chemical Properties of Silylenes.- 1. Polymerization Reactions.- A. Dimerization.- B. Polymerization.- 2. Insertion Reactions.- A. Si-H bonds.- B. Si-Si bonds.- C. Si-O bonds.- D. Halogen-Containing Bonds.- E. Other Hydrogen-Containing Bonds.- 3. Addition Reactions.- A. Olefins.- B. Conjugated Dienes.- C. Alkynes.- D. Aromatic Compounds.- E. Ketones.- References.- 5. Five-Membered Hetarynes.- I. Introduction.- 1. Role and Scope.- 2. Formulas and Nomenclature.- A. Carbocyclic Arynes.- B. Hetarynes.- C. Related Heterocyclic Species.- 3. Historical Perspective.- A. Development of the Aryne Concept.- B. History of the Five-Membered Hetaryne Hypothesis.- II. Chemistry of Arynes.- 1. Methods of Preparation.- A. General Considerations.- B. Arynes from Aryl Anion Intermediates.- C. Arynes by Loss of Nitrogen from Acyclic Substituents.- D. Arynes by Loss of Nitrogen from Cyclic Systems.- E. Arynes from Other Cyclic Systems.- F. Arynes from Other Sources.- 2. Methods of Detection.- A. Cine-Substitution.- B. Cycloaddition.- III. Five-Membered Hetarynes.- 1. Oxaarynes.- A. 2,3-Didehydrobenzofuran.- B. 2,3-Didehydrofuran.- C. Didehydromaleic Anhydride.- 2. Azaarynes.- A. 2,3-Didehydroindole.- B. 2,3-Didehydropyrrole.- C. 3,4-Didehydropyrrole.- D. Didehydromaleimide.- 3. Thiaarynes.- A. 2,3-Didehydrothiophene.- B. 3,4-Didehydrothiophene.- C. 2,3-Didehydrothianaphthene.- D. 2,3-Didehycrothianaphthene-1,1-dioxide.- 4. Selenaarynes.- 5. Diazaarynes.- A. Didehydroimidazole.- B. Didehydropyrazoles.- 6. Thiazaarynes.- A. Didehydrothiazole.- B. Didehydroisothiazoles.- C. Didehydro-1,2,5-thiadiazole.- 7. Benzdidehydro Five-Membered Heterocycles.- A. Benzdidehydrooxoles.- B. Benzdidehydroazoles.- C. Benzdidehydrothioles.- D. Didehydroazepinoazoles and Thioles.- 8. Five-Membered Carbocyclic Arynes.- A. Didehydroferrocene.- B. Didehydrocyclopentadiene Anion.- 9. Hetarynium Species.- IV. Summary.- 1. Electronic Factors.- 2. Geometric Factors.- 3. Kinetic Factors.- 4. Prognosis.- References and Notes.- 6. A Survey of Favorskii Rearrangement Mechanisms. Influence of the Nature and Strain of the Skeleton.- I. Introduction.- 1. Favorskii reaction mechanisms.- II. Symmetrical Mechanisms.- 1. Cyclopropanone Mechanism and Experimental Evidence for the Symmetrical Intermediate.- 2. First Step of the Mechanism.- A. Cyclohexane Substrates.- 3. Second Step of the Mechanism.- A. Open-Chain Juxtacyclic Substrates.- B. Cyclohexane Substrates.- C. Influence of Structural Features on the Reactivity of Acyclic and Cyclic Substrates.- 4. Relative Stability of Zwitterion and Cyclopropanone.- A. Acyclic Substrates.- B. Cyclic Substrates.- 5. Conclusion.- III. Unsymmetrical Mechanism.- 1. Occurrence.- 2. Evidence for the Semibenzilic Mechanism.- A. Open-Chain Juxtacyclic Substrates.- B. Cyclic Substrates.- 3. Competition of the Cyclopropanone and the Semibenzilic Mechanisms as a Function of the Ring Strain and of the Base Strength.- 4. Conclusion.- IV. The Favorskii Rearrangement in Bridged Polycyclic and Cage Compounds.- 1. Results and Discussion.- 2. Secondary Reactions in Bridged Bicyclic and Cage Compounds.- 3. Conclusion.- V. General Conclusion.- References.

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