1
|
Dalling AG, Späth G, Fürstner A. Total Synthesis of the Tetracyclic Pyridinium Alkaloid epi-Tetradehydrohalicyclamine B. Angew Chem Int Ed Engl 2022; 61:e202209651. [PMID: 35971850 PMCID: PMC9826155 DOI: 10.1002/anie.202209651] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Indexed: 01/11/2023]
Abstract
The first total synthesis of a tetracyclic marine pyridinium alkaloid hinged on recent advances in chemoselectivity management: While many classical methods failed to afford the perceptively simple pyridine-containing core of the target, nickel/iridium photoredox dual catalysis allowed the critical C-C bond to be formed in good yield. Likewise, ring closing alkyne metathesis (RCAM) worked well in the presence of the unhindered pyridine despite the innately Lewis acidic Mo(+6) center of the alkylidyne catalyst. Finally, an iridium catalyzed hydrosilylation was uniquely effective in reducing a tertiary amide without compromising an adjacent pyridine and the lateral double bonds; this transformation is largely without precedent. The second strained macrocycle enveloping the core was closed by intramolecular N-alkylation with formation of the pyridinium unit; the reaction proceeded site- and chemoselectively in the presence of an a priori more basic tertiary amine.
Collapse
Affiliation(s)
| | - Georg Späth
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim/RuhrGermany
| |
Collapse
|
2
|
Dalling AG, Späth G, Fürstner A. Total Synthesis of the Tetracyclic Pyridinium Alkaloid epi‐Tetradehydrohalicyclamine B. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Andrew G. Dalling
- Max-Planck-Institut für Kohlenforschung: Max-Planck-Institut fur Kohlenforschung Organometallic Chemistry GERMANY
| | - Georg Späth
- Max-Planck-Institut für Kohlenforschung: Max-Planck-Institut fur Kohlenforschung Organometallic Chemistry GERMANY
| | - Alois Fürstner
- Max-Planck-Institut fur Kohlenforschung Organometallic Chemistry Kaiser-Wilhelm-Platz 1 45470 Mülheim/Ruhr GERMANY
| |
Collapse
|
3
|
Wang X, Wang Z, Ma X, Huang Z, Sun K, Gao X, Fu S, Liu B. Asymmetric Total Synthesis of Shizukaol J, Trichloranoid C and Trishizukaol A. Angew Chem Int Ed Engl 2022; 61:e202200258. [PMID: 35102682 DOI: 10.1002/anie.202200258] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Indexed: 01/14/2023]
Abstract
The asymmetric total synthesis of three lindenane sesquiterpenoid oligomers, shizukaol J, trichloranoid C and trishizukaol A, has been accomplished concisely in 15, 16 and 18 longest linear steps, respectively. The expeditious construction of molecular architectures was facilitated by Nelson's catalytic asymmetric ketene-aldehyde cycloaddition, a sequence of allylic alkylation/reduction/acidic cyclization to forge a lactone, and a double aldol condensation cascade to construct the 5/6 bicyclic system. Diastereoselective nucleophilic substitution promoted by a phase transfer catalyst constructed the C11 quaternary stereogenic center, thus prompting synthetic efficacy toward shizukaol J. The synthesis of trichloranoid C and trishizukaol A was achieved after a cascade involving furanyl diene formation and a Diels-Alder reaction, as well as a one-pot sequence involving furan oxidation and global deprotection. Furthermore, our biological evaluation revealed that two compounds exhibited unexpected toxicity against tumor cell lines.
Collapse
Affiliation(s)
- Xiao Wang
- College of Chemistry, Sichuan University, 29 Wangjiang Rd., Chengdu, Sichuan, 610064, China
| | - Zhuang Wang
- College of Chemistry, Sichuan University, 29 Wangjiang Rd., Chengdu, Sichuan, 610064, China
| | - Xianjian Ma
- College of Chemistry, Sichuan University, 29 Wangjiang Rd., Chengdu, Sichuan, 610064, China
| | - Zhengsong Huang
- College of Chemistry, Sichuan University, 29 Wangjiang Rd., Chengdu, Sichuan, 610064, China
| | - Ke Sun
- School of Pharmaceutical Sciences, Xiamen University, South Xiangan Rd., Xiamen, Fujian, 361102, China
| | - Xiang Gao
- School of Pharmaceutical Sciences, Xiamen University, South Xiangan Rd., Xiamen, Fujian, 361102, China
| | - Shaomin Fu
- College of Chemistry, Sichuan University, 29 Wangjiang Rd., Chengdu, Sichuan, 610064, China
| | - Bo Liu
- College of Chemistry, Sichuan University, 29 Wangjiang Rd., Chengdu, Sichuan, 610064, China
| |
Collapse
|
4
|
Wang X, Wang Z, Ma X, Huang Z, Sun K, Gao X, Fu S, Liu B. Asymmetric Total Synthesis of Shizukaol J, Trichloranoid C and Trishizukaol A. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202200258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Xiao Wang
- College of Chemistry Sichuan University 29 Wangjiang Rd. Chengdu Sichuan 610064 China
| | - Zhuang Wang
- College of Chemistry Sichuan University 29 Wangjiang Rd. Chengdu Sichuan 610064 China
| | - Xianjian Ma
- College of Chemistry Sichuan University 29 Wangjiang Rd. Chengdu Sichuan 610064 China
| | - Zhengsong Huang
- College of Chemistry Sichuan University 29 Wangjiang Rd. Chengdu Sichuan 610064 China
| | - Ke Sun
- School of Pharmaceutical Sciences Xiamen University South Xiangan Rd. Xiamen Fujian 361102 China
| | - Xiang Gao
- School of Pharmaceutical Sciences Xiamen University South Xiangan Rd. Xiamen Fujian 361102 China
| | - Shaomin Fu
- College of Chemistry Sichuan University 29 Wangjiang Rd. Chengdu Sichuan 610064 China
| | - Bo Liu
- College of Chemistry Sichuan University 29 Wangjiang Rd. Chengdu Sichuan 610064 China
| |
Collapse
|
5
|
Hillenbrand J, Korber JN, Leutzsch M, Nöthling N, Fürstner A. Canopy Catalysts for Alkyne Metathesis: Investigations into a Bimolecular Decomposition Pathway and the Stability of the Podand Cap. Chemistry 2021; 27:14025-14033. [PMID: 34293239 PMCID: PMC8518412 DOI: 10.1002/chem.202102080] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Indexed: 11/28/2022]
Abstract
Molybdenum alkylidyne complexes with a trisilanolate podand ligand framework ("canopy catalysts") are the arguably most selective catalysts for alkyne metathesis known to date. Among them, complex 1 a endowed with a fence of lateral methyl substituents on the silicon linkers is the most reactive, although fairly high loadings are required in certain applications. It is now shown that this catalyst decomposes readily via a bimolecular pathway that engages the Mo≡CR entities in a stoichiometric triple-bond metathesis event to furnish RC≡CR and the corresponding dinuclear complex, 8, with a Mo≡Mo core. In addition to the regular analytical techniques, 95 Mo NMR was used to confirm this unusual outcome. This rapid degradation mechanism is largely avoided by increasing the size of the peripheral substituents on silicon, without unduly compromising the activity of the resulting complexes. When chemically challenged, however, canopy catalysts can open the apparently somewhat strained tripodal ligand cages; this reorganization leads to the formation of cyclo-tetrameric arrays composed of four metal alkylidyne units linked together via one silanol arm of the ligand backbone. The analogous tungsten alkylidyne complex 6, endowed with a tripodal tris-alkoxide (rather than siloxide) ligand framework, is even more susceptible to such a controlled and reversible cyclo-oligomerization. The structures of the resulting giant macrocyclic ensembles were established by single-crystal X-ray diffraction.
Collapse
Affiliation(s)
- Julius Hillenbrand
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - J. Nepomuk Korber
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Markus Leutzsch
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Nils Nöthling
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| | - Alois Fürstner
- Max-Planck-Institut für Kohlenforschung45470Mülheim an der RuhrMülheim/RuhrGermany
| |
Collapse
|