17092-41-0Relevant articles and documents
Total Synthesis and Structure Revision of Boholamide A
Han, Fangzhi,Liu, Guangju,Zhang, Xuhai,Ding, Yahui,Wang, Liang,Wu, Yijing,Chen, Yue,Zhang, Quan
supporting information, p. 4976 - 4980 (2021/06/30)
The 15-membered cyclic depsipeptide boholamide A and an epimer were prepared by total synthesis for the first time, thus leading to a revision of C6 stereochemistry in the originally proposed structure of natural boholamide A. This convergent route features achievement of a macro-lactamization step in a gram scale. The revised boholamide A was sythesized with 16 linear steps in 5.46% overall yield. This work facilitates the investigations of boholamide A as a potential hypoxia-selective anticancer agent.
A Specific Blend of Drakolide and Hydroxymethylpyrazines: An Unusual Pollinator Sexual Attractant Used by the Endangered Orchid Drakaea micrantha
Bohman, Bj?rn,Tan, Monica M. Y.,Phillips, Ryan D.,Scaffidi, Adrian,Sobolev, Alexandre N.,Moggach, Stephen A.,Flematti, Gavin R.,Peakall, Rod
supporting information, p. 1124 - 1128 (2019/12/24)
Bioactive natural products underpin the intriguing pollination strategy used by sexually deceptive orchids. These compounds, which mimic the sex pheromones of the female insect, are emitted in particular blends to lure male insect pollinators of specific species. By combining methods from field biology, analytical chemistry, electrophysiology, crystallography, and organic synthesis, we report that an undescribed β-hydroxylactone, in combination with two specific hydroxymethylpyrazines, act as pollinator attractants in the rare hammer orchid Drakaea micrantha. This discovery represents an unusual case of chemically unrelated compounds being used together as a sexual attractant. Furthermore, this is the first example of the identification of pollinator attractants in an endangered orchid, enabling the use of chemistry in orchid conservation. Our synthetic blend is now available to be used in pollinator surveys to locate suitable sites for plant conservation translocations.
Enantioselective Synthesis of the Proposed Structure of Santinol D
Xiong, Xin,Wu, Yikang,Liu, Bo
, p. 948 - 960 (2020/02/15)
In connection with structural verification of santinol D, a unique tricylglycerol isolated from Helichrysum italicum subsp. microphyllum, four possible isomers of its C-2'''and C-4''' centers were synthesized. The two enolizable chiral centers were installed with pre-defined absolute configurations using Evans alkylation and aldol condensation, respectively. The extra chiral center introduced in the aldol condensation was removed by Dess–Martin oxidation to convert the adjacent methine group into the highly enolizable subunit of an α-alkyl-β-keto ester at the end of the synthesis. The synthetic isomers provided unequivocal physical and NMR data for every single enantiomer and thus provided the information required for the configurational assignment of this natural product. With the aid of a model compound, the racemization of such species was examined polarimetrically under several sets of typical conditions and the rates were also calculated from the corresponding kinetics data.
Desymmetrization of C2-Symmetric Bis(Boronic Esters) by Zweifel Olefinations
Linne, Yannick,Sch?nwald, Axel,Wei?bach, Sebastian,Kalesse, Markus
supporting information, p. 7998 - 8002 (2020/06/09)
anti-Configured 1,3-dimethyl deoxypropionate motifs are important sub structures in natural products. Herein, we describe a bidirectional approach for the rapid construction of natural products featuring such motifs by using C2-symmetrical 1,3-bis(boronic esters). As for its application in convergent syntheses it was important to establish a selective mono-Zweifel olefination we describe the scope and limitations by using different 1,3-bis(boronic esters) and nucleophiles. This protocol takes advantage of the combination of the Hoppe–Matteson–Zweifel chemistry, which was elegantly put into practice by Aggarwal et al. In order to show its applicability the total syntheses of two natural products, serricornin and (+)-invictolide, were performed.
Synthesis and fungicidal activity of 2-methylalkyl isonicotinates and nicotinates
Huras, Bogumi?a,Zakrzewski, Jerzy,Krawczyk, Maria,Bombińska, Danuta,Cieniecka-Ros?onkiewicz, Anna,Michalczyk, Alicja
, p. 509 - 517 (2017/02/15)
Abstract: Homologs and analogs of 2-methylheptyl isonicotinate (new, natural antifungal and antibacterial antibiotic isolated from Streptomyces sp. 201): racemic 2-methylalkyl isonicotinates 4 and nicotinates 5 and enantiomerically enriched in the R and S isomers, 2-methylpentyl isonicotinate and nicotinate were obtained. Fungistatic activity of the compounds was evaluated. Nicotinates 5a–c show significant activity against phytopathogenic fungi: Fusarium culmorum, Phytophthora cactorum, Rhizoctonia solani. The activity of the enantiomerically enriched compounds was comparable to the activity of racemic ones. There was no significant difference in fungistatic activity between the enantiomerically enriched R and S isomers. Investigated compounds and their oxalates have proven to be active against chalkbrood disease caused by fungal species Ascosphaera apis. The activity of the nicotinates 5a and 5b and oxalates 5a–c against Ascosphaera apis was higher than the activity of oxalic acid itself. Especially high activity was shown for 2-methylbutyl nicotinate 5a and oxalate of 2-methylpentyl nicotinate 5b. Graphical abstract: [InlineMediaObject not available: see fulltext.]
Asymmetric hydrogenation of allylic alcohols using ir?N,P-Complexes
Li, Jia-Qi,Liu, Jianguo,Krajangsri, Suppachai,Chumnanvej, Napasawan,Singh, Thishana,Andersson, Pher G.
, p. 8342 - 8349 (2018/05/23)
In this study, a series of γ,γ-disubstituted and β,γ-disubstituted allylic alcohols were prepared and successfully hydrogenated using suitable N,P-based Ir complexes. High yields and excellent enantioselectivities were obtained for most of the substrates studied. This investigation also revealed the effect of the acidity of the N,P?Ir-complexes on the acid-sensitive allylic alcohols. DFT ΔpKa calculations were used to explain the effect of the N,P-ligand on the acidity of the corresponding Ir-complex. The selectivity model of the reaction was used to accurately predict the absolute configuration of the hydrogenated alcohols.
PROCESSES FOR THE SYNTHESIS OF CHIRAL 1-ALKANOLS
-
Paragraph 0220; 0221, (2016/12/01)
The invention relates to highly enantioselective processes for the synthesis of chiral 1-alkanols via Zr-catalyzed asymmetric carboalumination of alkenes.
Direct Generation of Triketide Stereopolyads via Merged Redox-Construction Events: Total Synthesis of (+)-Zincophorin Methyl Ester
Kasun, Zachary A.,Gao, Xin,Lipinski, Radoslaw M.,Krische, Michael J.
supporting information, p. 8900 - 8903 (2015/08/03)
(+)-Zincophorin methyl ester is prepared in 13 steps (longest linear sequence). A bidirectional redox-triggered double anti-crotylation of 2-methyl-1,3-propane diol directly assembles the triketide stereopolyad spanning C4-C12, significantly enhancing step economy and enabling construction of (+)-zincophorin methyl ester in nearly half the steps previously required.
PROCESSES FOR THE SYNTHESIS OF CHIRAL 1-ALKANOLS
-
Paragraph 00113, (2015/07/23)
The invention relates to highly enantioselective processes for the synthesis of chiral 1-alkanols via Zr-catalyzed asymmetric carboalumination of alkenes.
Widely applicable synthesis of enantiomerically pure tertiary alkyl-containing 1-alkanols by zirconium-catalyzed asymmetric carboalumination of alkenes and palladium- or copper-catalyzed cross-coupling
Xu, Shiqing,Lee, Ching-Tien,Wang, Guangwei,Negishi, Ei-Ichi
, p. 1829 - 1835 (2013/09/02)
A highly enantioselective and widely applicable method for the synthesis of various chiral 2-alkyl-1-alkanols, especially those of feeble chirality, has been developed. It consists of zirconium-catalyzed asymmetric carboalumination of alkenes (ZACA), lipase-catalyzed acetylation, and palladium- or copper-catalyzed cross-coupling. By virtue of the high selectivity factor (E) associated with iodine, either (S)- or (R)-enantiomer of 3-iodo-2-alkyl-1- alkanols (1), prepared by ZACA reaction of allyl alcohol, can be readily purified to the level of ≥99 % ee by lipase-catalyzed acetylation. A variety of chiral tertiary alkyl-containing alcohols, including those that have been otherwise difficult to prepare, can now be synthesized in high enantiomeric purity by Pd- or Cu-catalyzed cross-coupling of (S)-1 or (R)-2 for introduction of various primary, secondary, and tertiary carbon groups with retention of all carbon skeletal features. These chiral tertiary alkyl-containing alcohols can be further converted into the corresponding acids with full retention of the stereochemistry. The synthetic utility of this method has been demonstrated in the highly enantioselective (≥99 % ee) and efficient syntheses of (R)-2-methyl-1-butanol and (R)- and (S)-arundic acids. Look, mom, one hand! 2-Alkyl-1-alkanols of feeble chirality have been synthesized by a sequence of zirconium-catalyzed asymmetric carboalumination of alkenes (ZACA), lipase-catalyzed acetylation, and Pd- or Cu-catalyzed cross-coupling in high enantiomeric purity of ≥99 % ee. The synthetic utility of this method has been demonstrated in highly enantioselective and efficient syntheses of (R)-2-methyl-1-butanol, (R)- and (S)-arundic acids. Copyright
