1565-80-6Relevant articles and documents
Electrophysiological and behavioral activity of secondary metabolites in the confused flour beetle, tribolium confusum
Verheggen,Ryne,Olsson,Arnaud,Lognay,Hoegberg,Persson,Haubruge,Loefstedt
, p. 525 - 539 (2007)
Several previous studies have addressed pheromone communication in various flour beetles (Coleoptera: Tenebrionidae), including the confused flour beetle, Tribolium confusum (du Val). Different stereoisomers of 4,8-dimethyldecanal (DMD) were reported as the only components of an aggregation pheromone, but the behavioral activity of DMD is low. In the present study, additional previously reported secondary metabolites (benzoquinones and hydrocarbons) were tested for electrophysiological activity (EAG) with both sexes of T. confusum. Two benzoquinones and three monoenic hydrocarbons elicited significant EAG activity from both male and female antennae. There was an elevated male EAG response (vs. the females) to two out of the three hydrocarbons and for both quinones. The EAG-active compounds were subsequently investigated for behavioral activity in a walking bioassay. Benzoquinones are considered toxic and have been assigned a function as alarm substances in flour beetles, but we found that methyl-1, 4-benzoquinone in intermediate concentrations was attractive to both male and female beetles and could therefore act as an aggregation pheromone component. Males were also attracted to ethyl-1,4-benzoquinone. The corresponding hydroquinones, presumed precursors of the benzoquinones, did not elicit any electrophysiological response and were not tested for behavioral activity. The unsaturated hydrocarbons (1-tetradecene, 1-pentadecene, and 1-hexadecene) elicited significant EAG responses from both male and female antennae and were also attractive in the behavioral assay. Our results show that several beetle-produced compounds, in addition to 4,8-dimethyldecanal, may be part of a complex pheromone system in flour beetles and play a role in mediating aggregation in T. confusum.
Polyunsaturated C-Glycosidic 4-Hydroxy-2-pyrone Derivatives: Total Synthesis Shows that Putative Orevactaene Is Likely Identical with Epipyrone A
Preindl, Johannes,Schulthoff, Saskia,Wirtz, Conny,Lingnau, Julia,Fürstner, Alois
supporting information, p. 7525 - 7530 (2017/06/13)
Orevactaene and epipyrone A were previously thought to comprise the same polyunsaturated tail but notably different C-glycosylated 4-hydroxy-2-pyrone head groups. Total synthesis now shows that the signature bicyclic framework assigned to orevactaene is a chimera; the compound is almost certainly identical with epipyrone A, whose previously unknown stereochemistry has also been established during this study. Key to success was the ready formation of the bicyclic core of putative orevactaene by a sequence of two alkyne cycloisomerization reactions using tungsten and gold catalysis. Equally important was the flexibility in the assembly process gained by the use of heterobimetallic polyunsaturated modules whose termini could be selectively and consecutively addressed in a practical one-pot cross-coupling sequence.
PROCESSES FOR THE SYNTHESIS OF CHIRAL 1-ALKANOLS
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Paragraph 0214; 0215; 0216; 0217, (2016/12/01)
The invention relates to highly enantioselective processes for the synthesis of chiral 1-alkanols via Zr-catalyzed asymmetric carboalumination of alkenes.
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
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Paragraph 00110; 00111, (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
A comparison between oxazoline-imidazolinylidene, -imidazolylidine, -benzimidazolylidene hydrogenation catalysts
Khumsubdee, Sakunchai,Fan, Yubo,Burgess, Kevin
, p. 9969 - 9974 (2013/10/22)
Imidazolinylidene, imidazolylidine, benzimidazolylidene complexes 1a-c were prepared and tested in asymmetric hydrogenations of a series of largely unfunctionalized alkenes. Similarities and differences in the catalytic performance of these complexes were rationalized in terms of the predicted mechanisms of these reactions, and their relative tendencies to generate protons under the hydrogenation conditions.
Synthesis of enantiomerically pure model compounds of the glucose-6-phosphate-T1-translocase inhibitors kodaistatins A-D. Inferences with regard to the stereostructure of the natural products
Wüster, Thomas,Kaczybura, Natasza,Brückner, Reinhard,Keller, Manfred
, p. 7785 - 7809 (2013/08/23)
The kodaistatins A and C (5a,b) inhibit a step in glucose-metabolism at ～100 nM concentrations. This makes them potential 'leads' in the therapy of diabetes. We elucidated the (S)-configuration of the side-chain stereocenter of kodaistatin A by ozonolysis/reduction. The 13C NMR shifts of kodaistatin A model cis-11 suggest that the diol moiety in the dihydroxycyclopentanone core of kodaistatin is trans-configured. This model was prepared from the Feringa lactone (21) and (S)-2-methylbutanal (27) in 23 steps (14 steps in the longest linear sequence). We employed the same strategy for the simplified kodaistatin A model iso-cis-12, which resulted from the same substrates in 11 steps (6 steps in the longest linear sequence). The cyclopentenone cores of both targets stemmed from a C4+C1 approach. The C4 components were masked 'tartaric ketones' (16a,b) and a masked 'tartaric aldehyde' (18), respectively. The C1 components were the lithium-derivatives of the side-chain bearing phosphonates 19 and 22, respectively. The desired acylation/deprotonation/Horner-Wadsworth- Emmons tandem reaction succeeded in a single operation with the 'tartaric aldehyde' 18 but required partly or exclusively additional operations when we incorporated the 'tartaric ketones' 16a or 16b, respectively. The 'tartaric ketones' 16a,b contained an α-siloxyethyl substituent. It is noteworthy that it had to be introduced by adding the benzyltrimethylammonium enolate of lactone 18 to acetaldehyde because the lithium enolate of this lactone fragmented by an acetone-releasing β-elimination.
Enantioselective sorption of alcohols in a homochiral metal-organic framework
Suh, Kyungwon,Yutkin, Maxim P.,Dybtsev, Danil N.,Fedin, Vladimir P.,Kim, Kimoon
supporting information; experimental part, p. 513 - 515 (2012/01/19)
Single-crystal X-ray diffraction study reveals the host-guest interactions between a homochiral metal-organic framework and two enantiomers of a chiral alcohol providing the key driving force for the enantioselective sorption of alcohols in the framework.
Highly enantioselective iridium-catalyzed hydrogenation of α,β-unsaturated esters
Li, Jia-Qi,Quan, Xu,Andersson, Pher G.
supporting information, p. 10609 - 10616 (2012/11/07)
α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals. Asymmetric hydrogenation: A variety of α,β-unsaturated esters were hydrogenated with high enantioselectivities (see scheme). The hydrogenated products have been used in synthetic transformations as well as in formal total syntheses. Copyright
