1
|
Taniguchi T, Mutmainah, Takimoto S, Suzuki T, Watanabe S, Matsuda F, Umezawa T, Monde K. Scope and limitations of absolute configuration determination of allenic natural products using the CCC stretching VCD signal. Org Biomol Chem 2023; 21:569-574. [PMID: 36541676 DOI: 10.1039/d2ob01520j] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The allene functional group in natural products isolated so far exists in a non-racemic form, but its axial chirality is difficult to elucidate. Allenes exhibit a characteristic antisymmetric CCC stretching mode at around 1950 cm-1, and their VCD properties have not been studied in detail. This work, for the first time, applied VCD spectroscopy to allenic natural products and allenic molecules with other asymmetric centers focusing on the antisymmetric CCC stretching mode. This vibrational mode yielded a negligibly weak VCD signal for several molecules, but in the presence of electron-withdrawing and/or conjugating substituents, it generated a stronger one. Its sign was found to be influenced by the nature of substituents. These findings should deepen the understanding of the VCD properties of the allene functional group and should be useful for future studies of chiral allenes.
Collapse
Affiliation(s)
- Tohru Taniguchi
- Frontier Research Center for Advanced Material and Life Science, Faculty of Advanced Life Science, Hokkaido University, North 21 West 11, Sapporo 001-0021, Japan.
| | - Mutmainah
- Graduate School of Life Science, Hokkaido University, North 21 West 11, Sapporo 001-0021, Japan
| | - Shu Takimoto
- Graduate School of Life Science, Hokkaido University, North 21 West 11, Sapporo 001-0021, Japan
| | - Takahiro Suzuki
- Department of Chemistry, Faculty of Science, Hokkaido University, North 10 West 8, Sapporo 060-0810, Japan
| | - Soichiro Watanabe
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, North 13 West 8, Sapporo 060-8628, Japan
| | - Fuyuhiko Matsuda
- Division of Environmental Materials Science, Graduate School of Environmental Science, Hokkaido University, North 10 West 5, Sapporo 060-0810, Japan
| | - Taiki Umezawa
- Division of Environmental Materials Science, Graduate School of Environmental Science, Hokkaido University, North 10 West 5, Sapporo 060-0810, Japan
| | - Kenji Monde
- Frontier Research Center for Advanced Material and Life Science, Faculty of Advanced Life Science, Hokkaido University, North 21 West 11, Sapporo 001-0021, Japan.
| |
Collapse
|
2
|
Enantioselective Total Synthesis of Multifidene, a Sex Pheromone of Brown Algae. ORGANICS 2022. [DOI: 10.3390/org3030015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The total synthesis of multifidene, a sex pheromone found in brown algae, is described. The synthesis features the highly enantioselective and diastereoselective addition reaction of an aldehyde to a nitroolefin in the presence of a Hayashi–Jørgensen catalyst and a Nef reaction initiated by visible light irradiation. These key reactions enabled the 11-step synthesis from commercially available compounds. The synthetic pheromones are examined with gametes.
Collapse
|
3
|
Effective Synthesis and Antifouling Activity of Dolastatin 16 Derivatives. Mar Drugs 2022; 20:md20020124. [PMID: 35200652 PMCID: PMC8876244 DOI: 10.3390/md20020124] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/01/2022] [Accepted: 02/01/2022] [Indexed: 11/17/2022] Open
Abstract
Some derivatives of dolastatin 16, a depsipeptide natural product first obtained from the sea hare Dolabella auricularia, were synthesized through second-generation synthesis of two unusual amino acids, dolaphenvaline and dolamethylleuine. The second-generation synthesis enabled derivatizations such as functionalization of the aromatic ring in dolaphenvaline. The derivatives of fragments and whole structures were evaluated for antifouling activity against the cypris larvae of Amphibalanus amphitrite. Small fragments inhibited the settlement of the cypris larvae at potent to moderate concentrations (EC50 = 0.60-4.62 μg/mL), although dolastatin 16 with a substituent on the aromatic ring (24) was much less potent than dolastatin 16.
Collapse
|