1
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Watanabe A, Hikone Y, Nagatomo M, Inoue M. Conversion of Phorbol into Des-D-Ring Tricycle and Crotonianoid B via Peroxidation Reaction. Org Lett 2024; 26:4335-4339. [PMID: 38738923 DOI: 10.1021/acs.orglett.4c01363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Phorbol (1) has a tetracyclic ABCD-ring and is readily isolable from a natural source. We previously synthesized 1 and 16 structurally related natural products using common ABC-ring intermediate 2. Here we report a new synthetic route to 2 using 1 as a starting material. Key features of the synthesis are chemoselective removal of the D-ring via cyclopropane opening, peroxidation, and retro-aldol reactions. The high utility of the peroxidation was further demonstrated in the first synthesis of crotonianoid B (9).
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Affiliation(s)
- Ayumu Watanabe
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yuto Hikone
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masanori Nagatomo
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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2
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Watanabe A, Nagatomo M, Hirose A, Hikone Y, Kishimoto N, Miura S, Yasutake T, Abe T, Misumi S, Inoue M. Total Syntheses of Phorbol and 11 Tigliane Diterpenoids and Their Evaluation as HIV Latency-Reversing Agents. J Am Chem Soc 2024; 146:8746-8756. [PMID: 38486375 DOI: 10.1021/jacs.4c01589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Tigliane diterpenoids possess exceptionally complex structures comprising common 5/7/6/3-membered ABCD-rings and disparate oxygen functionalities. While tiglianes display a wide range of biological activities, compounds with HIV latency-reversing activity can eliminate viral reservoirs, thereby serving as promising leads for new anti-HIV agents. Herein, we report collective total syntheses of phorbol (13) and 11 tiglianes 14-24 with various acylation patterns and oxidation states, and their evaluation as HIV latency-reversing agents. The syntheses were strategically divided into five stages to increase the structural complexity. First, our previously established sequence enabled the expeditious preparation of ABC-tricycle 9 in 15 steps. Second, hydroxylation of 9 and ring-contractive D-ring formation furnished phorbol (13). Third, site-selective attachment of two acyl groups to 13 produced four phorbol diesters 14-17. Fourth, the oxygen functionalities were regio- and stereoselectively installed to yield five tiglianes 18-22. Fifth, further oxidation to the most densely oxygenated acerifolin A (23) and tigilanol tiglate (24) was realized through organizing a 3D shape of the B-ring. Assessment of the HIV latency-reversing activities of the 12 tiglianes revealed seven tiglianes (14-17 and 22-24) with 20- to 300-fold improved efficacy compared with prostratin (12), a representative latency-reversing agent. Therefore, the robust synthetic routes to a variety of tiglianes with promising activities devised in this study provide opportunities for advancing HIV eradication strategies.
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Affiliation(s)
- Ayumu Watanabe
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Masanori Nagatomo
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Akira Hirose
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yuto Hikone
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Naoki Kishimoto
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Satoshi Miura
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Tae Yasutake
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Towa Abe
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Shogo Misumi
- Department of Environmental and Molecular Health Sciences, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973, Japan
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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3
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Wang Y, Jin Z, Zhou L, Lv X. Recent advances in [4 + 4] annulation of conjugated heterodienes with 1,4-dipolar species for the synthesis of eight-membered heterocycles. Org Biomol Chem 2024; 22:252-268. [PMID: 38062977 DOI: 10.1039/d3ob01626a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Numerous eight-membered heterocycles are of significance in biological chemistry, the pharmaceutical industry, agrochemistry, and materials science. However, the assembly of eight-membered heterocycles is usually challenging due to the unfavorable enthalpic and entropic barriers of the transition states during the ring formation. Tremendous efforts have been devoted to the development of synthetic routes to eight-membered heterocycles. Despite these developments, the exploration of more strategies for the facile and effective assembly of eight-membered heterocyclic molecules in a single vessel under mild conditions is still highly desirable. The conjugated heterodiene-participating [4 + 4] annulation serves as a convenient and robust strategy for the synthesis of eight-membered heterocycles from easily accessible starting materials. In recent years, great progress has been achieved in this attractive field. In this short review, we highlighted the recent advances in the synthesis of eight-membered heterocycles via cascade reactions based on [4 + 4] annulation of conjugated heterodienes with 1,4-dipolar species. The brief backgrounds, the general reactions, the proposed mechanisms and their features are summarized. The prospects and challenges of this field are also outlined at the end of this review. In addition, to highlight the importance and practicality of these reactions, the properties of several series of eight-membered heterocycles have also been introduced briefly.
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Affiliation(s)
- Yahui Wang
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, 688 Yinbing Rd, Jinhua 321004, People's Republic of China.
| | - Zefeng Jin
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, 688 Yinbing Rd, Jinhua 321004, People's Republic of China.
| | - Liejin Zhou
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, 688 Yinbing Rd, Jinhua 321004, People's Republic of China.
- Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan
| | - Xin Lv
- Key Laboratory of the Ministry of Education for Advanced Catalysis Materials, College of Chemistry and Materials Science, Zhejiang Normal University, 688 Yinbing Rd, Jinhua 321004, People's Republic of China.
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