Synthetic Organic Photochemistry

621 Pages·2005·11.22 MB·English

by  Axel G. Griesbeck

Synthetic Organic
Photochemistry
Copyright © 2005 by Marcel Dekker
MOLECULAR AND SUPRAMOLECULAR
PHOTOCHEMISTRY
Series Editors
V.Ramamurthy
Professor
Department of Chemistry
Tulane University
New Orleans,Louisiana
Kirk S.Schanze
Professor
Department of Chemistry
University of Florida
Gainesville,Florida
1. Organic Photochemistry, edited by V. Ramamurthy and Kirk S.
Schanze
2. Organic and Inorganic Photochemistry, edited by V. Ramamurthy
and Kirk S. Schanze
3. Organic Molecular Photochemistry, edited by V. Ramamurthy
and Kirk S. Schanze
4. Multimetallic and Macromolecular Inorganic Photochemistry,
edited by V. Ramamurthy and Kirk S. Schanze
5. Solid State and Surface Photochemistry, edited by V.
Ramamurthy and Kirk S. Schanze
6. Organic, Physical, and Materials Photochemistry, editedby V.
Ramamurthy and Kirk S. Schanze
7. Optical Sensors and Switches, edited by V. Ramamurthy and
Kirk S. Schanze
8. Understanding and Manipulating Excited-State Processes,
edited by V. Ramamurthy and Kirk S. Schanze
9. Photochemistry of Organic Molecules in Isotropic and
Anisotropic Media,edited by V. Ramamurthy and Kirk S.
Schanze
10. Semiconductor Photochemistry and Photophysics, edited by V.
Ramamurthy and Kirk S. Schanze
11. Chiral Photochemistry, edited by Yoshihisa Inoue
and V. Ramamurthy
12. Synthetic Organic Photochemistry, edited by Axel G. Griesbeck
and Jochen Mattay
Copyright © 2005 by Marcel Dekker
Synthetic Organic
Photochemistry
edited by
Axel G. Griesbeck
Universität zu Köln,
Köln, Germany
Jochen Mattay
Universität Bielefeld,
Bielefeld, Germany
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Copyright © 2005 by Marcel Dekker
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Preface
Photochemistry is a highly valuable tool for modern organic synthesis.
It has had a very strong first period of prosperity in the early fifties and
sixties of the last century, when numerous light-induced reactions were
discovered, modified and applied to synthetic problems. A milestone of
development is related to the famous Woodward-Hoffmann rules and the
photochemical reactions which served as the experimental basis. Subse-
quently, expectations from the ‘‘synthetic community’’ were high and the
actualoutputinfactremarkable,aschemistsbecameawareofthereactivity
potential of electronic excited states of a molecule. Indeed, photochemistry
means in many cases a multiplication of reactivity options, i.e. in addition
to the ground state, the electronically excited singlets and triplets show
differentchemicalbehaviorandoftendiffersoremarkablythattheybehave
as completely new molecules. If you don’t want to use them, however,
they simply disappear again by radiative or non-radiative pathways (a key
principlealsoofgreenchemistry).Thetechniquesoftime-resolvedspectros-
copy approaching new fascinating time domains (‘‘femtochemistry’’) in the
last decades, enable the photochemistry community to describe a photo-
physical process in full detail and also to predict photochemical reactivity.
In spite of these exceptional advantages, light-induced reactions were
onlylittlebylittleacceptedbythesyntheticorganiccommunity.Upto1995,
onlyabout1%oftheproceduresandreactionsinOrganicSynthesesandin
Organic Reactions dealt with photochemistry! In our opinion this results
from two major problems:
First, photochemistry is always linked to photophysical aspects—the
nature of the excited state, its lifetime, its radiative and non-radiative
iii
Copyright © 2005 by Marcel Dekker
iv Preface
deactivation paths have to be considered (and to be optimized) in order
to design a productive light-induced process—which makes things less
easy. Second, photochemical processes require appropriate (and some-
times also expensive) equipment, a fact which often discouraged the
interested user.
In the meanwhile, interdisciplinary research became more and more
essentialandphotochemistrybecameaperfectexampleasapowerfulbridge
between chemistry, physics, and biology, between material science, life
science, and synthesis.
Until recently organic photochemistry has only partially focused on
stereoselective synthesis, one of the major challenges and research areas in
modern organic synthesis. This situation has dramatically changed in the
last decade and highly chemo-, regio-, diastereo- as well as enantioselective
reactionshavebeendeveloped.Chemistsallovertheworldbecameawareof
the fascinating synthetic opportunities of electronically excited molecules
and definitely this will lead to a new period of prosperity. Photochemical
reactions can be performed at low temperatures, in the solid or liquid state
or under gas-phase conditions, with spin-selective direct excitation or
sensitization, and even multi-photon processes start to enter the synthetic
scenery.
Withcontributionsfrom24internationalsubjectauthorities,Synthetic
Organic Photochemistry comprises a leading-edge presentation of the most
recent and in-demand applications of photochemical methodologies.
Outlining a wide assortment of reaction types, entailing cycloadditions,
cyclizations, isomerizations, rearrangements, and other organic syntheses,
this reference also ties in critical considerations that overlap in modern
photochemistry and organic chemistry, such as stereoselectivity. Select
experimental procedures demonstrate the industrial and academic value of
reactions presented in the text.
Containing a remarkable 2113 references, this volume
(cid:1) reviews [2þ2], [4þ2], and ene photooxygenation reactions,
(cid:1) illustrates photocycloadditions of alkenes to excited alkenes or
carbonyls,
(cid:1) clarifies abstractions of g- and (g(cid:2)n) hydrogens by excited
carbonyls,
(cid:1) describes di-p-methane and oxa-di-p-methane rearrangements,
(cid:1) explores photoinduced electron transfer cyclizations using radical
ions,
(cid:1) studies photogenerated nitrene additions to p-bonds,
(cid:1) surveys reactions with photoinduced aromatic nucleophilic
substitutions,
Copyright © 2005 by Marcel Dekker
Preface v
(cid:1) coversseveralotherphotochemicalmethodsforspecificsyntheses,
(cid:1) inspects medium effects on photoinduced processes.
Synthetic Organic Photochemistry is an ideal resource for photo-
chemists, organic and physical chemists, and graduate students in these
disciplines.
Axel G. Griesbeck
Jochen Mattay
Copyright © 2005 by Marcel Dekker
Contents
Preface iii
Contributors ix
1. Synthetic Organic Photochemistry 1
Axel G. Griesbeck and Jochen Mattay
2. Abstraction of g-Hydrogens by Excited Carbonyls 11
Peter J. Wagner
3. Abstraction of (g(cid:2)n)-Hydrogen by Excited Carbonyls 41
Pablo Wessig and Olaf Mu¨hling
4. Photocycloadditions of Alkenes to Excited Carbonyls 89
Axel G. Griesbeck
5. Photocycloaddition of Alkenes to Excited Alkenes 141
Steven A. Fleming
6. Di-p-Methane Rearrangement 161
Diego Armesto, Maria J. Ortiz, and Antonia R. Agarrabeitia
7. Oxa-Di-p-Methane Rearrangements 189
V. Jayathirtha Rao and Axel G. Griesbeck
vii
Copyright © 2005 by Marcel Dekker
viii Contents
8. Photocycloaddition of Cycloalk-2-enones to Alkenes 211
Paul Margaretha
9. Photocycloaddition of Alkenes (Dienes) to Dienes
([4þ2]/[4þ4]) 239
Scott McN. Sieburth
10. Photoinduced Electron Transfer Cyclizations via Radical Ions 269
Michael Oelgemo¨ller, Jens Otto Bunte, and Jochen Mattay
11. Photo-oxygenation of the [4þ2] and [2þ2] Type 299
Maria Rosaria Iesce
12. Photo-oxygenation of the Ene-Type 365
Edward L. Clennan
13. Photogenerated Nitrene Addition to p-Bonds 391
Hans-Werner Abraham
14. C¼C Photoinduced Isomerization Reactions 417
Tadashi Mori and Yoshihisa Inoue
15. Photoinduced CX Cleavage of Benzylic Substrates 453
Angelo Albini and Maurizio Fagnoni
16. Photoinduced Aromatic Nucleophilic
Substitution Reactions 495
Roberto A. Rossi
17. Ortho-, Meta-, and Para-Photocycloaddition of Arenes 529
Norbert Hoffmann
18. Medium Effects on Photochemical Processes: Organized 553
and Confined Media
Lakshmi S. Kaanumalle, Arunkumar Natarajan,
and V. Ramamurthy
Copyright © 2005 by Marcel Dekker