Triplet acetylenes as synthetic equivalents of 1,2-bicarbenes: Phantom n,π* state controls reactivity in triplet photocycloaddition

Journal of the American Chemical Society

Volumn 127, Issue 12, 2005, Pages 4270-4285

  Zeidan, Tarek A ^a   Kovalenko, Serguei V ^a   Manoharan, Mariappan ^a   Clark, Ronald J ^a   Ghiviriga, Ion ^b   Alabugin, Igor V ^a  

^a FLORIDA STATE UNIVERSITY   (United States)

^b UNIVERSITY OF FLORIDA   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ADDITION REACTIONS; COORDINATION REACTIONS; PHOTOCHEMICAL REACTIONS; POLYMERS; SUBSTITUTION REACTIONS; SUPRAMOLECULAR CHEMISTRY;

1,2-BICARBENES; REACTIVITY; SYNTHETIC EQUIVALENTS; TRIPLET ACETYLENES;

ACETYLENE;

1,2 BICARBENE DERIVATIVE; 1,4 CYCLOHEXADIENE; 4 PYRIDYL DERIVATIVE; 4 TETRAFLUOROPYRIDYL DERIVATIVE; ACETYLENE; ACETYLENE DERIVATIVE; ALKADIENE; CARBENOID; COORDINATION COMPOUND; CYCLOOCTANE DERIVATIVE; METAL; PHENYL GROUP; POLYMER; PYRAZINE; PYRAZINE DERIVATIVE; PYRIDINE; PYRIDINE DERIVATIVE; RADICAL; SOLVENT; TETRACYCLO[3.3.0.0.0]OCTANE DERIVATIVE; TRICYCLO[3.2.1.0]OCT 2 ENE DERIVATIVE; UNCLASSIFIED DRUG;

ARTICLE; CALCULATION; CARBON NUCLEAR MAGNETIC RESONANCE; CHEMICAL BOND; CHEMICAL REACTION; CHEMICAL STRUCTURE; CONCENTRATION RESPONSE; CONTROL SYSTEM; CYCLIZATION; CYCLOADDITION; ELECTRON TRANSPORT; MASS SPECTROMETRY; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; PHOTOCHEMISTRY; PHOTOCYCLOADDITION; PROTON NUCLEAR MAGNETIC RESONANCE; QUANTUM YIELD; REACTION ANALYSIS; SOLVENT EFFECT; STRUCTURE ANALYSIS; SUBSTITUTION REACTION; SUPRAMOLECULAR CHEMISTRY; SYNTHESIS; TECHNIQUE; TEMPERATURE DEPENDENCE; X RAY CRYSTALLOGRAPHY;

EID: 16244388925     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja043803l     Document Type: Article

References (145)

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78. 2 carbon centers are neglected.
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80. x* configuration.
81. Calculations including the self-consistent reaction field (SCRF) in the gas-phase computations are included in the Supporting Information.
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85. For the interesting consequences of the presence of n,π* states in pyridines and other azaheterocycles, see: ref 44 and Kasha, M. Radiat. Res. Suppl. 1960, 2, 243. Goodman, L. J. Mol. Spectrosc. 1961, 6, 109. Lower, S. K.; El-Sayed, M. A. Chem. Rev. 1966, 66, 199.
86. Unlike the highly exothermic PET to the singlet excited state, PET from 1,4-CHD to the triplet excited state becomes endothermic due to the lower energy of the latter state.
87. A particularly thorough study: Pryor, W. A.; Tang, F. Y.; Tang, R. H.; Church, D. F. J. Am. Chem. Soc. 1982, 104, 2885. Zipse, H.; He, J.; Houk, K. N.; Giese, B. J. Am. Chem. Soc. 1991, 113, 4324. Tararov, V. I.; Kuznetzov, N. Y.; Bakhmutov, V. I.; Ikonnikov, N. S.; Bubnov, Y. N.; Khrustalev, V. N.; Saveleva, T. F.; Belokon, Y. N. J. Chem. Soc., Perkin Trans. 1 1997, 20, 3101. Heberger, K.; Lopata, A. J. Org. Chem. 1998, 63, 8646. Arnaud, R.; Bugaud, N.; Vetere, V.; Barone, V. J. Am. Chem. Soc. 1998, 120, 5733. Roberts, B. P.; Smits, T. M. J. Chem. Soc., Perkin Trans. 2 1999, 12, 2691. Lalevee, J.; Allonas, X.; Fouassier, J. J. Phys. Chem. A 2004, 108, 4326.
88. A particularly thorough study: Pryor, W. A.; Tang, F. Y.; Tang, R. H.; Church, D. F. J. Am. Chem. Soc. 1982, 104, 2885. Zipse, H.; He, J.; Houk, K. N.; Giese, B. J. Am. Chem. Soc. 1991, 113, 4324. Tararov, V. I.; Kuznetzov, N. Y.; Bakhmutov, V. I.; Ikonnikov, N. S.; Bubnov, Y. N.; Khrustalev, V. N.; Saveleva, T. F.; Belokon, Y. N. J. Chem. Soc., Perkin Trans. 1 1997, 20, 3101. Heberger, K.; Lopata, A. J. Org. Chem. 1998, 63, 8646. Arnaud, R.; Bugaud, N.; Vetere, V.; Barone, V. J. Am. Chem. Soc. 1998, 120, 5733. Roberts, B. P.; Smits, T. M. J. Chem. Soc., Perkin Trans. 2 1999, 12, 2691. Lalevee, J.; Allonas, X.; Fouassier, J. J. Phys. Chem. A 2004, 108, 4326.
89. A particularly thorough study: Pryor, W. A.; Tang, F. Y.; Tang, R. H.; Church, D. F. J. Am. Chem. Soc. 1982, 104, 2885. Zipse, H.; He, J.; Houk, K. N.; Giese, B. J. Am. Chem. Soc. 1991, 113, 4324. Tararov, V. I.; Kuznetzov, N. Y.; Bakhmutov, V. I.; Ikonnikov, N. S.; Bubnov, Y. N.; Khrustalev, V. N.; Saveleva, T. F.; Belokon, Y. N. J. Chem. Soc., Perkin Trans. 1 1997, 20, 3101. Heberger, K.; Lopata, A. J. Org. Chem. 1998, 63, 8646. Arnaud, R.; Bugaud, N.; Vetere, V.; Barone, V. J. Am. Chem. Soc. 1998, 120, 5733. Roberts, B. P.; Smits, T. M. J. Chem. Soc., Perkin Trans. 2 1999, 12, 2691. Lalevee, J.; Allonas, X.; Fouassier, J. J. Phys. Chem. A 2004, 108, 4326.
90. A particularly thorough study: Pryor, W. A.; Tang, F. Y.; Tang, R. H.; Church, D. F. J. Am. Chem. Soc. 1982, 104, 2885. Zipse, H.; He, J.; Houk, K. N.; Giese, B. J. Am. Chem. Soc. 1991, 113, 4324. Tararov, V. I.; Kuznetzov, N. Y.; Bakhmutov, V. I.; Ikonnikov, N. S.; Bubnov, Y. N.; Khrustalev, V. N.; Saveleva, T. F.; Belokon, Y. N. J. Chem. Soc., Perkin Trans. 1 1997, 20, 3101. Heberger, K.; Lopata, A. J. Org. Chem. 1998, 63, 8646. Arnaud, R.; Bugaud, N.; Vetere, V.; Barone, V. J. Am. Chem. Soc. 1998, 120, 5733. Roberts, B. P.; Smits, T. M. J. Chem. Soc., Perkin Trans. 2 1999, 12, 2691. Lalevee, J.; Allonas, X.; Fouassier, J. J. Phys. Chem. A 2004, 108, 4326.
91. A particularly thorough study: Pryor, W. A.; Tang, F. Y.; Tang, R. H.; Church, D. F. J. Am. Chem. Soc. 1982, 104, 2885. Zipse, H.; He, J.; Houk, K. N.; Giese, B. J. Am. Chem. Soc. 1991, 113, 4324. Tararov, V. I.; Kuznetzov, N. Y.; Bakhmutov, V. I.; Ikonnikov, N. S.; Bubnov, Y. N.; Khrustalev, V. N.; Saveleva, T. F.; Belokon, Y. N. J. Chem. Soc., Perkin Trans. 1 1997, 20, 3101. Heberger, K.; Lopata, A. J. Org. Chem. 1998, 63, 8646. Arnaud, R.; Bugaud, N.; Vetere, V.; Barone, V. J. Am. Chem. Soc. 1998, 120, 5733. Roberts, B. P.; Smits, T. M. J. Chem. Soc., Perkin Trans. 2 1999, 12, 2691. Lalevee, J.; Allonas, X.; Fouassier, J. J. Phys. Chem. A 2004, 108, 4326.
92. A particularly thorough study: Pryor, W. A.; Tang, F. Y.; Tang, R. H.; Church, D. F. J. Am. Chem. Soc. 1982, 104, 2885. Zipse, H.; He, J.; Houk, K. N.; Giese, B. J. Am. Chem. Soc. 1991, 113, 4324. Tararov, V. I.; Kuznetzov, N. Y.; Bakhmutov, V. I.; Ikonnikov, N. S.; Bubnov, Y. N.; Khrustalev, V. N.; Saveleva, T. F.; Belokon, Y. N. J. Chem. Soc., Perkin Trans. 1 1997, 20, 3101. Heberger, K.; Lopata, A. J. Org. Chem. 1998, 63, 8646. Arnaud, R.; Bugaud, N.; Vetere, V.; Barone, V. J. Am. Chem. Soc. 1998, 120, 5733. Roberts, B. P.; Smits, T. M. J. Chem. Soc., Perkin Trans. 2 1999, 12, 2691. Lalevee, J.; Allonas, X.; Fouassier, J. J. Phys. Chem. A 2004, 108, 4326.
93. A particularly thorough study: Pryor, W. A.; Tang, F. Y.; Tang, R. H.; Church, D. F. J. Am. Chem. Soc. 1982, 104, 2885. Zipse, H.; He, J.; Houk, K. N.; Giese, B. J. Am. Chem. Soc. 1991, 113, 4324. Tararov, V. I.; Kuznetzov, N. Y.; Bakhmutov, V. I.; Ikonnikov, N. S.; Bubnov, Y. N.; Khrustalev, V. N.; Saveleva, T. F.; Belokon, Y. N. J. Chem. Soc., Perkin Trans. 1 1997, 20, 3101. Heberger, K.; Lopata, A. J. Org. Chem. 1998, 63, 8646. Arnaud, R.; Bugaud, N.; Vetere, V.; Barone, V. J. Am. Chem. Soc. 1998, 120, 5733. Roberts, B. P.; Smits, T. M. J. Chem. Soc., Perkin Trans. 2 1999, 12, 2691. Lalevee, J.; Allonas, X.; Fouassier, J. J. Phys. Chem. A 2004, 108, 4326.
94. Note that ISC should occur somewhere along the reaction hypersurface in order to reach the final product 37. The lack of [2+2] adducts suggests that ISC occurs after the initially formed diradical 32 undergoes one of the further steps in the cyclization cascade. Five possible ISC points are shown, but it is possible that ISC occurs even before these points.
95. For recent examples of 3-exo-trig cyclizations, see: Journet, M.; Malacria, M. J. Org. Chem. 1994, 59, 718. Srikrishna, A.; Danieldoss, S. J. Org. Chem. 1997, 62, 7863. Lange, G. L.; Merica, A. Tetrahedron Lett. 1999, 40, 7897. The first step of di-π-methane rearrangement can also be considered to be a 3-exo-trig cyclization when the excitation is mostly concentrated on one of the double bonds: Zimmerman, H. E.; Armesto, D. Chem. Rev. 1996, 96, 3065.
96. For recent examples of 3-exo-trig cyclizations, see: Journet, M.; Malacria, M. J. Org. Chem. 1994, 59, 718. Srikrishna, A.; Danieldoss, S. J. Org. Chem. 1997, 62, 7863. Lange, G. L.; Merica, A. Tetrahedron Lett. 1999, 40, 7897. The first step of di-π-methane rearrangement can also be considered to be a 3-exo-trig cyclization when the excitation is mostly concentrated on one of the double bonds: Zimmerman, H. E.; Armesto, D. Chem. Rev. 1996, 96, 3065.
97. For recent examples of 3-exo-trig cyclizations, see: Journet, M.; Malacria, M. J. Org. Chem. 1994, 59, 718. Srikrishna, A.; Danieldoss, S. J. Org. Chem. 1997, 62, 7863. Lange, G. L.; Merica, A. Tetrahedron Lett. 1999, 40, 7897. The first step of di-π-methane rearrangement can also be considered to be a 3-exo-trig cyclization when the excitation is mostly concentrated on one of the double bonds: Zimmerman, H. E.; Armesto, D. Chem. Rev. 1996, 96, 3065.
98. For recent examples of 3-exo-trig cyclizations, see: Journet, M.; Malacria, M. J. Org. Chem. 1994, 59, 718. Srikrishna, A.; Danieldoss, S. J. Org. Chem. 1997, 62, 7863. Lange, G. L.; Merica, A. Tetrahedron Lett. 1999, 40, 7897. The first step of di-π-methane rearrangement can also be considered to be a 3-exo-trig cyclization when the excitation is mostly concentrated on one of the double bonds: Zimmerman, H. E.; Armesto, D. Chem. Rev. 1996, 96, 3065.
99. Owsley, D. C.; Bloomfeild, J. J J. Am. Chem. Soc. 1971, 93, 782.
100. The [2+2] adducts are readily formed in reactions with alkenes such as cyclohexene and tetramethyl ethylene.
101. Monguchi, K.; Itoh, T.; Hirai, K.; Tomioka, H. J. Am. Chem. Soc. 2004, 126, 11900.
102. Control experiments ruled out a thermal homo-Diels-Alder reaction between 1,4-CHD and acetylene which is the other way to form compound 36.
103. Srinivasan, R.; Ors, J. A.; Brown, K. H.; Baum, T.; White, L. S.; Rossi, A. R. J. Am. Chem. Soc. 1980, 102, 5297.
104. Srinvasan, R.; Carlough, K. H. J. Am. Chem. Soc. 1967, 89, 4932. See also: Turro, N. J. Molecular Photochemistry, University Science Books: 1991; p 430. For MO and state correlation diagrams for the formation of five-membered biradicals in cyclizations of 1,4-pentadiene and 1,5-hexadiene, see: Gleiter, R.; Sander, W. Angew. Chem., Int. Ed. Engl. 1985, 24, 566. For the role of sigma bridge in these processes, see: Verhoeven, J. W. Recl. Trav. Chim. Pays-Bas 1980, 99, 375.
105. Srinvasan, R.; Carlough, K. H. J. Am. Chem. Soc. 1967, 89, 4932. See also: Turro, N. J. Molecular Photochemistry, University Science Books: 1991; p 430. For MO and state correlation diagrams for the formation of five-membered biradicals in cyclizations of 1,4-pentadiene and 1,5-hexadiene, see: Gleiter, R.; Sander, W. Angew. Chem., Int. Ed. Engl. 1985, 24, 566. For the role of sigma bridge in these processes, see: Verhoeven, J. W. Recl. Trav. Chim. Pays-Bas 1980, 99, 375.
106. Srinvasan, R.; Carlough, K. H. J. Am. Chem. Soc. 1967, 89, 4932. See also: Turro, N. J. Molecular Photochemistry, University Science Books: 1991; p 430. For MO and state correlation diagrams for the formation of five-membered biradicals in cyclizations of 1,4-pentadiene and 1,5-hexadiene, see: Gleiter, R.; Sander, W. Angew. Chem., Int. Ed. Engl. 1985, 24, 566. For the role of sigma bridge in these processes, see: Verhoeven, J. W. Recl. Trav. Chim. Pays-Bas 1980, 99, 375.
107. Srinvasan, R.; Carlough, K. H. J. Am. Chem. Soc. 1967, 89, 4932. See also: Turro, N. J. Molecular Photochemistry, University Science Books: 1991; p 430. For MO and state correlation diagrams for the formation of five-membered biradicals in cyclizations of 1,4-pentadiene and 1,5-hexadiene, see: Gleiter, R.; Sander, W. Angew. Chem., Int. Ed. Engl. 1985, 24, 566. For the role of sigma bridge in these processes, see: Verhoeven, J. W. Recl. Trav. Chim. Pays-Bas 1980, 99, 375.
108. Baldwin, J. E. J. Chem. Soc., Chem. Commun. 1976, 734.
109. This is a typical situation for diradical species. For a recent discussion and references, see: Doering, W. v. E.; Barsa, E. A. J. Am. Chem. Soc. 2004, 126, 12353. See also: Doering, W. v. E.; DeLuca, J. P. J. Am. Chem. Soc. 2003, 125, 10608. von Doering, W.; Cheng, X.; Lee, K.; Lin, Z. J. Am. Chem. Soc. 2003, 124, 11642.
110. This is a typical situation for diradical species. For a recent discussion and references, see: Doering, W. v. E.; Barsa, E. A. J. Am. Chem. Soc. 2004, 126, 12353. See also: Doering, W. v. E.; DeLuca, J. P. J. Am. Chem. Soc. 2003, 125, 10608. von Doering, W.; Cheng, X.; Lee, K.; Lin, Z. J. Am. Chem. Soc. 2003, 124, 11642.
111. This is a typical situation for diradical species. For a recent discussion and references, see: Doering, W. v. E.; Barsa, E. A. J. Am. Chem. Soc. 2004, 126, 12353. See also: Doering, W. v. E.; DeLuca, J. P. J. Am. Chem. Soc. 2003, 125, 10608. von Doering, W.; Cheng, X.; Lee, K.; Lin, Z. J. Am. Chem. Soc. 2003, 124, 11642.
112. The seminal study: (a) Hoffmann, R.; Imamura, A.; Hehre, W. J. J. Am. Chem. Soc. 1968, 90, 1499.
113. (b) Hoffmann, R. Acc. Chem. Res. 1971, 4, 1-9.
114. (c) Paddon-Row, M. N. Acc. Chem. Res. 1982, 15, 245.
115. (d) Gleiter, R.; Schafer, W. Acc. Chem. Res. 1990, 23, 369-375.
116. (e) Brodskaya, E. I.; Ratovskii, G. V.; Voronkov, M. G. Russ. Chem. Rev. 1993, 62, 975.
117. Logan, C. F.; Chen, P. J. Am. Chem. Soc. 1996, 118, 2113. Schottelius, M. J.; Chen, P. J. Am. Chem. Soc. 1996, 118, 4896. Kraka, E.; Cremer, D. J. Am. Chem. Soc. 2000, 122, 8245. Alabugin, I. V.; Manoharan, M. J. Am. Chem. Soc. 2003, 125, 4495.
118. Logan, C. F.; Chen, P. J. Am. Chem. Soc. 1996, 118, 2113. Schottelius, M. J.; Chen, P. J. Am. Chem. Soc. 1996, 118, 4896. Kraka, E.; Cremer, D. J. Am. Chem. Soc. 2000, 122, 8245. Alabugin, I. V.; Manoharan, M. J. Am. Chem. Soc. 2003, 125, 4495.
119. Logan, C. F.; Chen, P. J. Am. Chem. Soc. 1996, 118, 2113. Schottelius, M. J.; Chen, P. J. Am. Chem. Soc. 1996, 118, 4896. Kraka, E.; Cremer, D. J. Am. Chem. Soc. 2000, 122, 8245. Alabugin, I. V.; Manoharan, M. J. Am. Chem. Soc. 2003, 125, 4495.
120. Logan, C. F.; Chen, P. J. Am. Chem. Soc. 1996, 118, 2113. Schottelius, M. J.; Chen, P. J. Am. Chem. Soc. 1996, 118, 4896. Kraka, E.; Cremer, D. J. Am. Chem. Soc. 2000, 122, 8245. Alabugin, I. V.; Manoharan, M. J. Am. Chem. Soc. 2003, 125, 4495.
121. For the most thorough recent discussion, see: Squires, R. R.; Cramer, C. J. J. Phys. Chem. A 1998, 102, 9072.
122. Antiperiplanar arrangement of the two radical centers strengthens their interaction even further: Prall, M.; Wittkopp, A.; Schreiner, P. R. J. Phys. Chem. A 2001, 105, 9265.
123. Freeman and co-workers have shown that the endo-isomer reacts two times faster than the exo-isomer, a result which is consistent with the larger exothermicity computed in the former case: Freeman, P. K.; Kupur, D. G.; Mallikarjuma Rao, V. N. Tetrahedron Lett. 1965, 37, 3301.
124. For interesting observations on reactivity of singlet and triplet 1,4-diradicals in photochemical reactions, see: Scaiano, J. C. Tetrahedron 1982, 38, 819. Wagner, P. J. Acc. Chem. Res. 1989, 22, 83. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1990, 112, 1281. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1991, 113, 6923. Griesbeck, A. G.; Mauder, H.; Stadtmüller, S. Acc. Chem. Res. 1994, 27, 70. Zand, A.; Park, B. S.; Wagner, P. J. J. Org. Chem. 1997, 62, 2326. Giese, B.; Wetstein, P.; Stahelin, C.; Barnosa, F.; Neuburger, M.; Zehnder, M.; Wessig, P. Angew. Chem., Int. Ed. 1999, 38, 2586. Abe, M.; Kawakami, T.; Ohata, S.; Nozaki, K.; Nojima, M. J. Am. Chem. Soc. 2004, 126, 2838. A recent thorough theoretical study of SOC in 1,4-diradicals: Kutateladze, A. G. J. Am. Chem. Soc. 2001, 123, 9279. Authoritative review: Doubleday, C., Jr.; Turro, N. J.; Wang, J. F. Acc. Chem. Res. 1989, 22, 199.
125. For interesting observations on reactivity of singlet and triplet 1,4-diradicals in photochemical reactions, see: Scaiano, J. C. Tetrahedron 1982, 38, 819. Wagner, P. J. Acc. Chem. Res. 1989, 22, 83. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1990, 112, 1281. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1991, 113, 6923. Griesbeck, A. G.; Mauder, H.; Stadtmüller, S. Acc. Chem. Res. 1994, 27, 70. Zand, A.; Park, B. S.; Wagner, P. J. J. Org. Chem. 1997, 62, 2326. Giese, B.; Wetstein, P.; Stahelin, C.; Barnosa, F.; Neuburger, M.; Zehnder, M.; Wessig, P. Angew. Chem., Int. Ed. 1999, 38, 2586. Abe, M.; Kawakami, T.; Ohata, S.; Nozaki, K.; Nojima, M. J. Am. Chem. Soc. 2004, 126, 2838. A recent thorough theoretical study of SOC in 1,4-diradicals: Kutateladze, A. G. J. Am. Chem. Soc. 2001, 123, 9279. Authoritative review: Doubleday, C., Jr.; Turro, N. J.; Wang, J. F. Acc. Chem. Res. 1989, 22, 199.
126. For interesting observations on reactivity of singlet and triplet 1,4-diradicals in photochemical reactions, see: Scaiano, J. C. Tetrahedron 1982, 38, 819. Wagner, P. J. Acc. Chem. Res. 1989, 22, 83. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1990, 112, 1281. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1991, 113, 6923. Griesbeck, A. G.; Mauder, H.; Stadtmüller, S. Acc. Chem. Res. 1994, 27, 70. Zand, A.; Park, B. S.; Wagner, P. J. J. Org. Chem. 1997, 62, 2326. Giese, B.; Wetstein, P.; Stahelin, C.; Barnosa, F.; Neuburger, M.; Zehnder, M.; Wessig, P. Angew. Chem., Int. Ed. 1999, 38, 2586. Abe, M.; Kawakami, T.; Ohata, S.; Nozaki, K.; Nojima, M. J. Am. Chem. Soc. 2004, 126, 2838. A recent thorough theoretical study of SOC in 1,4-diradicals: Kutateladze, A. G. J. Am. Chem. Soc. 2001, 123, 9279. Authoritative review: Doubleday, C., Jr.; Turro, N. J.; Wang, J. F. Acc. Chem. Res. 1989, 22, 199.
127. For interesting observations on reactivity of singlet and triplet 1,4-diradicals in photochemical reactions, see: Scaiano, J. C. Tetrahedron 1982, 38, 819. Wagner, P. J. Acc. Chem. Res. 1989, 22, 83. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1990, 112, 1281. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1991, 113, 6923. Griesbeck, A. G.; Mauder, H.; Stadtmüller, S. Acc. Chem. Res. 1994, 27, 70. Zand, A.; Park, B. S.; Wagner, P. J. J. Org. Chem. 1997, 62, 2326. Giese, B.; Wetstein, P.; Stahelin, C.; Barnosa, F.; Neuburger, M.; Zehnder, M.; Wessig, P. Angew. Chem., Int. Ed. 1999, 38, 2586. Abe, M.; Kawakami, T.; Ohata, S.; Nozaki, K.; Nojima, M. J. Am. Chem. Soc. 2004, 126, 2838. A recent thorough theoretical study of SOC in 1,4-diradicals: Kutateladze, A. G. J. Am. Chem. Soc. 2001, 123, 9279. Authoritative review: Doubleday, C., Jr.; Turro, N. J.; Wang, J. F. Acc. Chem. Res. 1989, 22, 199.
128. For interesting observations on reactivity of singlet and triplet 1,4-diradicals in photochemical reactions, see: Scaiano, J. C. Tetrahedron 1982, 38, 819. Wagner, P. J. Acc. Chem. Res. 1989, 22, 83. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1990, 112, 1281. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1991, 113, 6923. Griesbeck, A. G.; Mauder, H.; Stadtmüller, S. Acc. Chem. Res. 1994, 27, 70. Zand, A.; Park, B. S.; Wagner, P. J. J. Org. Chem. 1997, 62, 2326. Giese, B.; Wetstein, P.; Stahelin, C.; Barnosa, F.; Neuburger, M.; Zehnder, M.; Wessig, P. Angew. Chem., Int. Ed. 1999, 38, 2586. Abe, M.; Kawakami, T.; Ohata, S.; Nozaki, K.; Nojima, M. J. Am. Chem. Soc. 2004, 126, 2838. A recent thorough theoretical study of SOC in 1,4-diradicals: Kutateladze, A. G. J. Am. Chem. Soc. 2001, 123, 9279. Authoritative review: Doubleday, C., Jr.; Turro, N. J.; Wang, J. F. Acc. Chem. Res. 1989, 22, 199.
129. For interesting observations on reactivity of singlet and triplet 1,4-diradicals in photochemical reactions, see: Scaiano, J. C. Tetrahedron 1982, 38, 819. Wagner, P. J. Acc. Chem. Res. 1989, 22, 83. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1990, 112, 1281. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1991, 113, 6923. Griesbeck, A. G.; Mauder, H.; Stadtmüller, S. Acc. Chem. Res. 1994, 27, 70. Zand, A.; Park, B. S.; Wagner, P. J. J. Org. Chem. 1997, 62, 2326. Giese, B.; Wetstein, P.; Stahelin, C.; Barnosa, F.; Neuburger, M.; Zehnder, M.; Wessig, P. Angew. Chem., Int. Ed. 1999, 38, 2586. Abe, M.; Kawakami, T.; Ohata, S.; Nozaki, K.; Nojima, M. J. Am. Chem. Soc. 2004, 126, 2838. A recent thorough theoretical study of SOC in 1,4-diradicals: Kutateladze, A. G. J. Am. Chem. Soc. 2001, 123, 9279. Authoritative review: Doubleday, C., Jr.; Turro, N. J.; Wang, J. F. Acc. Chem. Res. 1989, 22, 199.
130. For interesting observations on reactivity of singlet and triplet 1,4-diradicals in photochemical reactions, see: Scaiano, J. C. Tetrahedron 1982, 38, 819. Wagner, P. J. Acc. Chem. Res. 1989, 22, 83. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1990, 112, 1281. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1991, 113, 6923. Griesbeck, A. G.; Mauder, H.; Stadtmüller, S. Acc. Chem. Res. 1994, 27, 70. Zand, A.; Park, B. S.; Wagner, P. J. J. Org. Chem. 1997, 62, 2326. Giese, B.; Wetstein, P.; Stahelin, C.; Barnosa, F.; Neuburger, M.; Zehnder, M.; Wessig, P. Angew. Chem., Int. Ed. 1999, 38, 2586. Abe, M.; Kawakami, T.; Ohata, S.; Nozaki, K.; Nojima, M. J. Am. Chem. Soc. 2004, 126, 2838. A recent thorough theoretical study of SOC in 1,4-diradicals: Kutateladze, A. G. J. Am. Chem. Soc. 2001, 123, 9279. Authoritative review: Doubleday, C., Jr.; Turro, N. J.; Wang, J. F. Acc. Chem. Res. 1989, 22, 199.
131. For interesting observations on reactivity of singlet and triplet 1,4-diradicals in photochemical reactions, see: Scaiano, J. C. Tetrahedron 1982, 38, 819. Wagner, P. J. Acc. Chem. Res. 1989, 22, 83. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1990, 112, 1281. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1991, 113, 6923. Griesbeck, A. G.; Mauder, H.; Stadtmüller, S. Acc. Chem. Res. 1994, 27, 70. Zand, A.; Park, B. S.; Wagner, P. J. J. Org. Chem. 1997, 62, 2326. Giese, B.; Wetstein, P.; Stahelin, C.; Barnosa, F.; Neuburger, M.; Zehnder, M.; Wessig, P. Angew. Chem., Int. Ed. 1999, 38, 2586. Abe, M.; Kawakami, T.; Ohata, S.; Nozaki, K.; Nojima, M. J. Am. Chem. Soc. 2004, 126, 2838. A recent thorough theoretical study of SOC in 1,4-diradicals: Kutateladze, A. G. J. Am. Chem. Soc. 2001, 123, 9279. Authoritative review: Doubleday, C., Jr.; Turro, N. J.; Wang, J. F. Acc. Chem. Res. 1989, 22, 199.
132. For interesting observations on reactivity of singlet and triplet 1,4-diradicals in photochemical reactions, see: Scaiano, J. C. Tetrahedron 1982, 38, 819. Wagner, P. J. Acc. Chem. Res. 1989, 22, 83. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1990, 112, 1281. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1991, 113, 6923. Griesbeck, A. G.; Mauder, H.; Stadtmüller, S. Acc. Chem. Res. 1994, 27, 70. Zand, A.; Park, B. S.; Wagner, P. J. J. Org. Chem. 1997, 62, 2326. Giese, B.; Wetstein, P.; Stahelin, C.; Barnosa, F.; Neuburger, M.; Zehnder, M.; Wessig, P. Angew. Chem., Int. Ed. 1999, 38, 2586. Abe, M.; Kawakami, T.; Ohata, S.; Nozaki, K.; Nojima, M. J. Am. Chem. Soc. 2004, 126, 2838. A recent thorough theoretical study of SOC in 1,4-diradicals: Kutateladze, A. G. J. Am. Chem. Soc. 2001, 123, 9279. Authoritative review: Doubleday, C., Jr.; Turro, N. J.; Wang, J. F. Acc. Chem. Res. 1989, 22, 199.
133. For interesting observations on reactivity of singlet and triplet 1,4-diradicals in photochemical reactions, see: Scaiano, J. C. Tetrahedron 1982, 38, 819. Wagner, P. J. Acc. Chem. Res. 1989, 22, 83. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1990, 112, 1281. Griesbeck, A. G.; Stadtmüller, S. J. Am. Chem. Soc. 1991, 113, 6923. Griesbeck, A. G.; Mauder, H.; Stadtmüller, S. Acc. Chem. Res. 1994, 27, 70. Zand, A.; Park, B. S.; Wagner, P. J. J. Org. Chem. 1997, 62, 2326. Giese, B.; Wetstein, P.; Stahelin, C.; Barnosa, F.; Neuburger, M.; Zehnder, M.; Wessig, P. Angew. Chem., Int. Ed. 1999, 38, 2586. Abe, M.; Kawakami, T.; Ohata, S.; Nozaki, K.; Nojima, M. J. Am. Chem. Soc. 2004, 126, 2838. A recent thorough theoretical study of SOC in 1,4-diradicals: Kutateladze, A. G. J. Am. Chem. Soc. 2001, 123, 9279. Authoritative review: Doubleday, C., Jr.; Turro, N. J.; Wang, J. F. Acc. Chem. Res. 1989, 22, 199.
134. A different electronic nature of the singlet excited states in pyridines vs pyrazines (n,π* vs π,π* as discussed in ref 45) may provide an explanation.
135. The photorearrangement is not sensitized by benzophenone, acetophenone, or xanthone.
136. (a) Shim, S. C.; Lee, T. S. J. Org. Chem. 1988, 53, 2410. Lee, T. S.; Lee, S. J.; Shim, S. C. J. Org. Chem. 1990, 55, 4544.
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138. (b) Lee, S. J.; Shim, S. C. Tetrahedron Lett. 1990, 31, 6197.
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140. (d) Lu, P. J.; Pan, W.; Jones, M., Jr. J. Am. Chem. Soc. 1998, 120, 8315.
141. (e) Laird, D. W.; Gilbert, J. C. J. Am. Chem. Soc. 2001, 123, 6704.
142. Manuscript is in preparation.
143. Kryschenko, Y. K.; Seidel, S. R.; Arif, A. M.; Stang, P. J. Am. Chem. Soc. 2003, 125, 5193.
144. For a recent review of supramolecular coordination chemistry, see: Leininger, S.; Olenyuk, B.; Stang, P. Chem. Rev. 2000, 100, 853. See also: Khlobystov, A. N.; Blake, A. J.; Chapness, N. R.; Lemenovskii, D. A.; Majouga, G.; Zyk, N. V.; Schroder, M. Coord. Chem. Rev. 2001, 222, 155.
145. For a recent review of supramolecular coordination chemistry, see: Leininger, S.; Olenyuk, B.; Stang, P. Chem. Rev. 2000, 100, 853. See also: Khlobystov, A. N.; Blake, A. J.; Chapness, N. R.; Lemenovskii, D. A.; Majouga, G.; Zyk, N. V.; Schroder, M. Coord. Chem. Rev. 2001, 222, 155.