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Wang Z, Yamazaki S, Morimoto T, Takashima H, Nakaoku A, Shimizu M, Ogawa A. Intramolecular cyclization reactions of arylpropargyl amides of electron-deficient α,β-alkenyl carboxylates and related compounds. Org Biomol Chem 2023; 21:2172-2187. [PMID: 36806878 DOI: 10.1039/d3ob00129f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Intramolecular cyclization reactions of arylpropargyl amides of electron-deficient α,β-alkenyl carboxylates such as fumarates and ethenetricarboxylates were investigated. The reaction of the fumaramides with a base, Et3N or DBU in xylenes at 140 °C under air gave benz[f]isoindoline derivatives in 21-63% yields. The benz[f]isoindolines may be produced via the formation of an allenic intermediate, intramolecular Diels-Alder reaction, proton transfer, and dehydrogenation by oxygen. The suitable bases and the product yields depend on the substituents on the benzene ring. On the other hand, the reaction of the amides of fumarate and ethenetricarboxylate by heating in DMSO gave aroyl-substituted pyrrolidine derivatives as major products, probably via addition of water under metal-free conditions. Furthermore, cyclization reactions of H and Me substituted alkyne derivatives were investigated for comparison. The selective formation of various types of products, such as ethyl 2-(1-benzyl-4-formyl-2-oxopyrrolidin-3-yl)acetate and diethyl 2-(1-benzyl-2-oxo-4-vinylidenepyrrolidin-3-yl)malonate, was found, depending upon the alkyne substituents and the reaction conditions. The reaction mechanisms have been discussed using density functional theory (DFT) calculations.
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Affiliation(s)
- Zhichao Wang
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Nakaku, Sakai, Osaka 599-8531, Japan
| | - Shoko Yamazaki
- Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan.
| | - Tsumoru Morimoto
- Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), Takayama, Ikoma, Nara 630-0192, Japan
| | - Hiroshi Takashima
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Ayane Nakaoku
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Makoto Shimizu
- Department of Chemistry, Faculty of Science, Nara Women's University, Nara 630-8506, Japan
| | - Akiya Ogawa
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Nakaku, Sakai, Osaka 599-8531, Japan
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