Synthetic Organic Photochemistry / Edition 1

by W.M. Horspool

Overview

Of all major branches of organic chemistry, I think none has undergone such a rapid, even explosive, development during the past twenty-five years as organic phohemistry. Prior to about 1960, phohemistry was still widely regarded as a branch of physical chemistry which might perhaps have oc­ casional applications in the generation of free radicals. Strangely enough, this attitude to the subject had developed despite such early signs of promise as the photodimerization of anthracene first observed by Fritzsche in 1866, and some strikingly original pioneering work by Ciamician and Silber in the early years of this century. These latter workers first reported such varied photo­ reactions as the photoisomerization of carvenone to carvone camphor, the photodimerization of stilbene, and the photoisomerization of o-nitrobenzal­ dehyde to o-nitrosobenzoic acid; yet organic chemists continued for another fifty years or so to rely almost wholly on thermal rather than phohemical methods of activation in organic synthesis-truly a dark age. When my colleagues and I first began in the 1950s to study the synthetic possibilities of photoexcitation in the chemistry of benzene and its derivatives, virtually all the prior reports had indicated that benzene was stable to ultraviolet radiation. Yet I think it fair to say that more different types of photoreactions than thermal reactions of the benzene ring are now known. Comparable growth of knowledge has occurred in other branches of organic phohemistry, and phohemical techniques have in particular made possible or simplified the synthesis of numerous highly strained organic molecules.

Product Details

ISBN-13:	9780306414497
Publisher:	Springer US
Publication date:	09/30/1984
Edition description:	1984
Pages:	534
Product dimensions:	5.98(w) x 9.02(h) x 0.05(d)

Table of Contents

1. Photoaddition and Phoyclization Processes of Aromatic Compounds.- 1. Introduction.- 2. Intermolecular Reactions.- 2.1. Arenes and Ethenes.- 2.2. Arenes and Acetylenes.- 2.3. Arenes and 1,3-Dienes.- 2.4. Acyclic Additions to Arenes and Reduction Processes.- 2.5. Arene Photodimerizations.- 3. Intramolecular Cyclization Processes.- 3.1. Arene-Ethene and Arene-Ethyne Systems.- 3.1.1. Hydrocarbon Systems.- 3.1.2. Aryl Enones.- 3.1.3. Aryl Ethenyl Ethers, Thioethers, and N- Aryl Enamines.- 3.1.4. Cyclizations of N-Arylanilides and N-Benzoylenamines.- 3.2. Aryl Butadiene and Butenyne Systems.- 3.3. Intramolecular Phooupling of Arenes.- 3.3.1. Stilbene-Phenanthrene-Type Cyclizations.- 3.3.2. Phooupling of Arenes with Intervening Units Other Than Ethylene.- 3.3.3. Coupling of Arenes as a Result of Halogen Acid Photoelimination.- 3.4. Phoyclizations of o-Substituted Arenes.- References.- 2. Enone Phohemical Cycloaddition in Organic Synthesis.- 1. Introduction.- 2. The Reaction Mechanism.- 3. Regiochemistry of Enone Cycloaddition.- 4. Stereochemistry of Enone Cycloaddition.- 5. Intramolecular Enone Cycloadditions.- 6. The de Mayo Reaction.- 6.1. Cyclic Diketones.- 6.2. Acyclic 1,3-Diketones.- 6.3. Intramolecular Additions of Enolized Diketones.- 7. Intermolecular Enone Cycloaddition.- 8. Phohemical Cycloaddition between Enones and Allenes.- References.- 3. Synthetic Aspects of Phohemical Electron Transfer Reactions.- 1. Introduction.- 1.1. Synthetic Applications of Phohemical Reactions.- 1.2. Electron Transfer in Excited-State Chemistry.- 1.2.1. Exciplex Formation and Decay.- 1.2.2. Electron Transfer Efficiencies and Rates.- 1.3. Chemical Consequence of Electron Transfer.- 1.3.1. General Survey and Predictions.- 1.3.2. Overview of Coverage.- 2. Reaction Pathways Followed in Electron Transfer Phohemistry.- 2.1. Alkenes and Strained Ring Hydrocarbons.- 2.1.1. Alkenes as Electron Acceptors and Donors.- 2.1.2. Cyclopropene Electron Transfer Phohemistry.- 2.1.3. Cyclopropanes and Other Strained Ring Systems as Electron Donors.- 2.2. Amines.- 2.2.1. General Considerations.- 2.2.2. Amine-Olefin Electron Transfer Phohemistry.- 2.2.3. Amine-Ketone Electron Transfer Phohemistry.- 2.3. Ketones.- 2.3.1. General Considerations.- 2.3.2. Ketone Electron Transfer Phohemistry.- 2.3.3. Quinone Electron Transfer Phohemistry.- 2.4. Electron Transfer Photooxygenations.- 2.4.1. General Considerations.- 2.4.2. Class 1 Photooxygenations.- 2.4.3. Class 2 Photooxygenations.- 2.4.4. Class 3 Photooxygenations.- 2.5. Aromatic Systems.- 2.5.1. Aromatic Photosubstitution Reactions.- 2.5.2. Photobenzylations by Electron Transfer Mechanisms.- 2.5.3. Birch and Related Photoreductions of Aromatic Compounds.- 2.6. Electron Transfer Phohemistry of Nitrogen Heteroaromatic Salts and Related Systems.- 2.6.1. General Considerations.- 2.6.2. Electron Transfer Phohemistry of Pyridinium and Related Salts.- 2.6.3. Iminium Salt Phohemistry.- 2.7. Other Electron Transfer Initiated Photoreactions.- 2.7.1. Olefin Cycloadditions and Retro Processes.- 2.7.2. Phthalimide Phohemistry.- 2.7.3. Photodecarboxylations.- 2.7.4. Metal Catalyzed Photoreactions.- References.- 4. Phthalimide and Its Derivatives.- 1. Introduction.- 2. Hydrogen Abstraction.- 2.1. Photoreduction and Photoaddition.- 2.2. Intramolecular Phoyclization.- 3. Reaction with Alkenes.- 3.1. Ring Expansion.- 3.2. Solvent Incorporation.- 3.3. Intramolecular Reaction.- 4. Cleavage Reactions.- 4.1.—-Cleavage.- 4.2.—-Cleavage.- 5. Spectra and Excited States.- 6. Summary.- References.- 5. Phohemical Addition Reactions in the Benzo(b)Thiophene, Benzo(b)Furan, and Indole Series.- 1. Introduction.- 1.1. Absorption and Emission Characteristics.- 2. Phohemistry.- 2.1. Oxetan Formation.- 2.2. Dimerization.- 2.3. Phohemical Reactions with Acetylene Esters.- 3. Benzo(b)thiophene.- 4. Indoles.- 5. Benzo(b)thiophenes.- 6. Benzo(b)furans.- 7. Thermal Reactions of the 2-Hetero-bicyclo(3.2.0)heptadienes.- 8. 1,3-Dimethylindole.- 9. Phoycloadditions of Benzo(b)thiophene to Alkenes.- References.- 6. Azirine Photolysis and Cycloaddition Reactions.- 1. Introduction.- 1.1. UV Spectra of Arylazirines.- 1.1.1. Evidence for Nitrile Ylide Formation.- 2. Cycloaddition Reactions.- 2.1. Addition with Electron-Deficient Olefins.- 2.1.1. Mechanism of Cycloaddition to Olefines.- 2.2. Addition to Aldehydes and Ketones.- 2.3. Addition to Esters.- 2.4. Additions to Acid Chloride and Anhydrides.- 2.5. Additions to Carbon Dioxide and Carbon Disulfide.- 2.6. Additions to Ketenes, Carbodiimides, Isocyanates, and Isothiocyanates.- 3. Photodimerization of Azirines.- 4. Intramolecular Cycloaddition Reactions.- 4.1. Rearrangement of 2-Vinylazirines.- 4.2. Rearrangements of Isoxazoles and Oxazoles.- 5. Mechanisms for Cycloaddition Reactions of Nitrile Ylides.- 5.1. The 1,1-Cycloaddition Process.- 5.2. Summary of 1,1-Cycloaddition Mode.- 5.3. Other Examples of 1,1-Cycloaddition.- 5.4. 1,1- and 1,3-Cycloaddition in Competition.- 6. Fragmentation Reactions.- 6.1. Competitive Involvement of Ylide Formation.- 7. Group Migration Reactions.- References.- 7. Photoremovable Protecting Groups.- 1. Introduction.- 2. Alcohols.- 2.1. Sulfonic Acid Esters.- 2.2. o-Nitrobenzyl Ethers.- 2.3. Nitrates, Nitrites, Dimelhylthiocarbamates, and Aryl Azides.- 3. Diols.- 4. Phenols.- 5. Aldehydes and Ketones.- 6. Carboxylic Acids and Amides.- 6.1. o-Nitrobenzyl Esters.- 6.2. o-Nitrophenylamino Derivatives.- 6.3. Phenacyl Esters.- 6.4. 2,4-Dinitrophenylthio Esters, Benzoin Esters, and Aryl Azides.- 7. Amines.- 7.1. Benzyloxycarbonyl Compounds.- 7.2. Sulfonamides.- 7.3. Formamides, N-Oxides, and 4,5-Diaryl-4-oxazoline-2-ones.- 8. Phosphates.- 9. Conclusion.- References.- 8. Phohemical Synthesis of Oxetans.- 1. Introduction.- 2. Reaction Mechanism.- 2.1. Carbonyl Excited States.- 2.2. Triplet Energies.- 2.3. Competing Reactions.- 2.4. Hydrogen Abstraction.- 3. Alkene Addends.- 3.1. Simply Substituted Alkenes.- 3.2. Dienes and Trienes.- 3.3. Allenes and Ketenimines.- 3.4. Electron-Deficient Alkenes.- 3.5. Vinyl Ethers.- 3.6. Heteroaromatics.- 4. Carbonyl Addends.- 4.1.—-Dicarbonyls.- 4.2. Quinones.- 4.3. Miscellaneous Carbonyls.- 4.4. Enones and Ynones.- 5. Intramolecular Cycloadditions.- 6. Chemical Reactions of Oxetans.- References.- 9. Equipment and Techniques.- 1. Mercury Vapor Lamps.- 2. Lamps in Conjunction with Filters.- 3. Phohemical Apparatus.- 4. Actinometry.- 4.1. Solution Phase Systems.- 4.2. Electronic Actinometers.- 5. Purity of Solvents and Gases.- References.