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Transition-Metal-Catalyzed Denitrogenative Transannulation: Converting Triazoles into Other Heterocyclic Systems 杜宇鎏 2012.10.13
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Page 2 2 1. Introduction In this PPT, recent progress of the transition metal catalyzed denitrogenative transannulation of a triazole ring, which was discovered in 2007, is discussed. 1,2,3-Triazoles are important heterocyclic units endowed with a broad spectrum of biological activities. They have been extensively used in medicinal chemistry, biochemistry, and in material science.
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Page 3 3 ◆ The Dimroth rearrangement 1)Otto Dimroth, Justus Liebig’s Annalen der Chemie, 1909, 364, 183-226. 2)Otto Dimroth, Walter Michaelis, Justus Liebig’s Annalen der Chemie, 1927, 459, 39-46.
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Page 4 4 The position of this equilibrium depends upon several factors, such as temperature, solvent, and the nature of the substituent (R 1 ) at C 7 of the triazole ring. The introduction of a halogen atom at C7 shifts the equilibrium to the right, which has been explained in terms of nonbonding repulsion between the lone pair of electrons on the halogen and nitrogen atom in the peri-position of the left. 1)G. Labb, Bull. Soc. Chim.Belg. 1990, 99, 281; 2)B. Abarca-Gonzlez, R. Ballesteros, F. Mojarred, G. Jones, D. J. Mouat, J. Chem. Soc. Perkin Trans. 1 1987, 1865.
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Page 5 5 2. Transannulation of Pyridotriazoles 1) S. Chuprakov, Frank, W. Hwang, V. Gevorgyan, Angew. Chem. 2007, 119, 4841; Angew. Chem. Int. Ed. 2007, 46, 4757. 2) V. Bagheri, M. P. Doyle, J. Taunton, E. E. Claxton, J. Org. Chem. 1988, 53, 6158.
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Page 6 6 S. Chuprakov, Frank, W. Hwang, V. Gevorgyan, Angew. Chem. 2007, 119, 4841; Angew. Chem. Int. Ed. 2007, 46, 4757. ◆ Transannulation with Alkynes and Nitriles
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Page 7 7
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Page 8 8 Proposed mechanism for transannulation of pyridotriazoles with alkynes and nitriles
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Page 9 9 3. Transannulation of N-Sulfonyl-1,2,3-triazoles 3.1. Transannulation with Alkynes, Nitriles, and Alkenes T. Horneff, S. Chuprakov, N. Chernyak, V. Gevorgyan, V. V. Fokin, J. Am. Chem. Soc. 2008, 130, 14972.
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Page 10 10 T. Miura, M. Yamauchi, M. Murakami, Chem. Commun. 2009, 1470. ◆ Nickel-catalyzed denitrogenative transannulation reaction of Nsulfonyl-1,2,3- triazoles with internal alkynes.
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Page 11 11 ◆ Proposed reaction pathway ◆ Possible role of the Lewis acid: A promotion of the ring–chain tautomerization, or an acceleration of the reductive elimination of nickel.
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Page 12 12 ◆ Transannulation of monocyclic triazoles with terminal alkynes into pyrroles B. Chattopadhyay, V. Gevorgyan, Org. Lett. 2011, 13, 3746.
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Page 13 13 ◆ Unique spot ◆ Deuterium labeling experiment
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Page 14 14 ◆ Proposed Mechanism
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Page 15 15 ◆ An efficient three-component semi-one-pot synthesis of the pyrrole
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Page 16 16 3.2 Synthesis of Rhodium(II) N-Triflyl Azavinyl Carbenes ◆ Sulfonylation reaction of 4-phenyl-NH-1,2,3-triazole N. Grimster, L. Zhang, V. V. Fokin, J. Am. Chem. Soc. 2010, 132, 2510.
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Page 17 17 ◆ Larock’s indole synthesis 1) I. Nakamura, T. Nemoto, N. Shiraiwa, M. Terada, Org. Lett. 2009, 11, 1055 2) R. C. Larock, E. K. Yum, J. Am. Chem. Soc. 1991, 113, 6689 4. Transannulation of N-Aroylbenzotriazoles
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Page 18 18 ◆ Proposed Mechanism
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Page 19 19 5. Transannulation of 1,2,3-Benzotriazinones T. Miura, M. Yamauchi, M. Murakami, Org. Lett. 2008, 10, 3085
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Page 20 20
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Page 21 21 ◆ Transannulation of 1,2,3-benzotriazinones with allenes M. Yamauchi, M. Morimoto, T. Miura, M. Murakami, J. Am. Chem. Soc. 2010, 132, 54.
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Page 22 22 ◆ The nature of the product varied depending upon the type of the phosphine ligand
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Page 23 23 ◆ Asymmetric version
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Page 24 24 ◆ Transannulation of benzotriazinones with 1,3-dienes and activated alkenes T. Miura, M. Morimoto, M. Yamauchi, M. Murakami, J. Org. Chem. 2010, 75, 5359.
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Page 25 25 ◆ With symmetrical 1,3-dienes ◆ With unsymmetrical 1,3-dienes
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Page 26 26 ◆ Transannulation with Isocyanides T. Miura, Y. Nishida, M. Morimoto, M. Yamauchi, M. Murakami, Org. Lett. 2011, 13, 1429.
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Page 27 27 6. Transannulation of 1,2,3,4-Benzothiazinones ◆ Transannulation with Allenes T. Miura, M. Yamauchi, A. Kosaka, M. Murakami, Angew. Chem. 2010, 122, 5075; Angew. Chem. Int. Ed. 2010, 49, 4955.
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Page 28 28 ◆ Highly diastereo- and enantioselective Rh(II)-catalyzed cyclopropanation Stepan Chuprakov, Sen Wai Kwok, Li Zhang, Lukas Lercher, and Valery V. Fokin, J. Am. Chem. Soc., 2009, 131, 18034–18035.
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Page 29 29 ◆ Catalytic Asymmetric C-H Insertions of Rhodium(II) Azavinyl Carbenes Stepan Chuprakov, Jamal A. Malik, Mikhail Zibinsky, and Valery V. Fokin, J. Am. Chem. Soc. 2011, 133, 10352-10355
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Page 30 30 ◆ Reactivity of N-(1,2,4-Triazolyl)-Substituted 1,2,3-Triazoles Mikhail Zibinsky and Valery V. Fokin, Org. Lett. 2011, 13, 4870-4872
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Page 31 31 Conclusion ◆ The PPT highlights the increasing interest in the development of transition metal catalyzed transannulation reactions. ◆ Triazoles serves as a complimentary methodology for construction of heterocycles as it allows a general and highly efficient synthesis of complex and highly functionalized aromatic nitrogen heterocycles with diverse substitution patterns. ◆ Unsymmetrical approaches in this area have not been developed as complete as the symmetrical ones, which require more attentions and researches.
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Thank You For Your Attention
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Page 33 33 ◆ Proposed mechanism for transannulation of pyridotriazoles with alkynes and nitriles
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Page 34 34 ◆ Proposed mechanism for the transannulation of N-sulfonyl-1,2,3-triazoles 17 with nitriles
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