41453-56-9Relevant academic research and scientific papers
Continuous Flow Z-Stereoselective Olefin Metathesis: Development and Applications in the Synthesis of Pheromones and Macrocyclic Odorant Molecules**
Browne, Duncan L.,Colombel-Rouen, Sophie,Crévisy, Christophe,Curbet, Idriss,Mauduit, Marc,McBride, Tom,Morvan, Jennifer,Roisnel, Thierry
supporting information, p. 19685 - 19690 (2021/08/06)
The first continuous flow Z-selective olefin metathesis process is reported. Key to realizing this process was the adequate choice of stereoselective catalysts combined with the design of an appropriate continuous reactor setup. The designed continuous process permits various self-, cross- and macro-ring-closing-metathesis reactions, delivering products in high selectivity and short residence times. This technique is exemplified by direct application to the preparation of a range of pheromones and macrocyclic odorant molecules and culminates in a telescoped Z-selective cross-metathesis/ Dieckmann cyclisation sequence to access (Z)-Civetone, incorporating a serial array of continually stirred tank reactors.
An unprecedented medium-chain diunsaturated n-acylhomoserine lactone from marine roseobacter group bacteria
Ziesche, Lisa,Wolter, Laura,Wang, Hui,Brinkhoff, Thorsten,Pohlner, Marion,Engelen, Bert,Wagner-D?bler, Irene,Schulz, Stefan
, (2019/01/11)
N-acylhomoserine lactones (AHLs), bacterial signaling compounds involved in quorum-sensing, are a structurally diverse group of compounds. We describe here the identification, synthesis, occurrence and biological activity of a new AHL, N-((2E,5Z)-2,5-dodecadienoyl)homoserine lactone (11) and its isomer N-((3E,5Z)-3,5-dodecadienoyl)homoserine lactone (13), occurring in several Roseobacter group bacteria (Rhodobacteraceae). The analysis of 26 strains revealed the presence of 11 and 13 in six of them originating from the surface of the macroalgae Fucus spiralis or sediments from the North Sea. In addition, 18 other AHLs were detected in 12 strains. Compound identification was performed by GC/MS. Mass spectral analysis revealed a diunsaturated C12 homoserine lactone as structural element of the new AHL. Synthesis of three likely candidate compounds, 11, 13 and N-((2E,4E)-2,4-dodecadienoyl)homoserine lactone (5), revealed the former to be the natural AHLs. Bioactivity test with quorum-sensing reporter strains showed high activity of all three compounds. Therefore, the configuration and stereochemistry of the double bonds in the acyl chain seemed to be unimportant for the activity, although the chains have largely different shapes, solely the chain length determining activity. In combination with previous results with other Roseobacter group bacteria, we could show that there is wide variance between AHL composition within the strains. Furthermore, no association of certain AHLs with different habitats like macroalgal surfaces or sediment could be detected.
Asymmetric Cα-Alkylation of Proline via Chirality Transfers of Conformationally Restricted Proline Derivative: Application to the Total Synthesis of (-)-Amathaspiramide F
Cho, Hyunkyung,Shin, Jae Eui,Lee, Seokwoo,Jeon, Hongjun,Park, Soojun,Kim, Sanghee
supporting information, p. 6121 - 6125 (2018/10/02)
An efficient strategy for the asymmetric synthesis of Cα-tetrasubstituted proline derivatives from proline has been established. A nitrogen-fused bicyclic system was devised to control the stereodynamics of proline. Through N-quaternizations with allylic electrophiles followed by [2,3]-rearrangements, the bicyclic proline system delivered enantioenriched Cα-tetrasubstituted prolines. This strategy was applied to the concise total synthesis of (-)-amathaspiramide F.
Asymmetric total synthesis of (+)-danicalipin A
Yoshimitsu, Takehiko,Nakatani, Ryo,Kobayashi, Akihiro,Tanaka, Tetsuaki
supporting information; experimental part, p. 908 - 911 (2011/04/23)
A convergent asymmetric total synthesis of (+)-danicalipin A is accomplished, in which two chlorinated fragments are stereoselectively joined by 1,3-dipolar coupling, leading to the confirmation of the absolute configuration of the natural product.(Figure Presented)
Synthesis of N-heterocycles, beta-amino acids, and allyl amines via aza-payne mediated reaction of ylides and hydroxy aziridines
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Page/Page column 36, (2009/01/23)
An ylide-based aza-Payne rearrangement of 2,3-aziridin-1-ols leads to an efficient process for the preparation of pyrrolidines. The aza-Payne rearrangement under the basic reaction conditions favors the formation of epoxy amines. Subsequent nucleophilic attack of the epoxide by the ylide yields a bis-anion, which upon a 5-exo-tet ring closure yields the desired pyrrolidine, thus completing the relay of the 3-membered the 5-membered nitrogen containing ring system. This process takes place with complete transfer of stereochemical fidelity, and can be applied to sterically hindered aziridinols.
Diastereomerically and enantiomerically pure 2,3-disubstituted pyrrolidines from 2,3-aziridin-1-ols using a sulfoxonium ylide: A one-carbon homologative relay ring expansion
Schomaker, Jennifer M.,Bhattacharjee, Somnath,Yan, Jun,Borhan, Babak
, p. 1996 - 2003 (2007/10/03)
An ylide-based aza-Payne rearrangement of 2,3-aziridin-1-ols leads to an efficient process for the preparation of pyrrolidines. The aza-Payne rearrangement under basic reaction conditions favors the formation of epoxy amines. Subsequent nucleophilic attack of the epoxide by the ylide yields a bis-anion, which upon a 5-exo-tet ring-closure yields the desired pyrrolidine, thus completing the relay of the three-membered to the five-membered nitrogen-containing ring system. This process takes place with complete transfer of stereochemical fidelity and can be applied to sterically hindered aziridinols.
Titanocene-catalyzed regiodivergent epoxide openings
Gansaeuer, Andreas,Fan, Chun-An,Keller, Florian,Keil, Jutta
, p. 3484 - 3485 (2008/01/01)
The first regiodivergent opening of unbiased epoxides providing the ring-opened products in high enantiomeric excess from racemic and exceptionally high enantiomeric excess from enantioenriched substrates in a double asymmetric process has been devised. It constitutes a more general case of the very important enantioselective openings of meso-epoxides. Copyright
Iridium complex-catalyzed allylic alkylation of allylic esters and allylic alcohols: Unique regio- and stereoselectivity
Takeuchi, Ryo,Kashio, Mikihiro
, p. 8647 - 8655 (2007/10/03)
An iridium complex was found to be an efficient catalyst for allylic alkylation of allylic esters with a stabilized carbon nucleophile. Highly regioselective alkylation at the substituted allylic terminus was achieved. The catalytic activity and regioselectivity were affected by the ligand used. The reaction of (E)-2-alkenyl acetates or 1-substituted 2-propeny acetates with dialkyl sodiomalonate in the presence of a catalytic amount of [Ir(COD)Cl]2/P(OPh)3 (P/Ir = 1-2) gave a product alkylated at the substituted allylic terminus in 95-99% selectivity. Construction of a quaternary carbon center is possible by this methodology. The reaction of 1,1-dialkyl-2-propenyl acetates gave a product alkylated at the disubstituted allylic terminus exclusively. (E)-2-Alken-1-ol could be successfully used as a substrate. The products alkylated at the substituted allylic terminus were obtained in 93-99% selectivity. A 31P NMR study of the reaction of [Ir(COD)Cl]2 with P(OPh)3 revealed that a catalytically active species is a monophosphite species. The π-acceptor property of P(OPh)3 promotes a carbonium ion character at the substituted allylic terminus and directs the nucleophilic attack to this position. The stereochemistry of the allyl system affected the regioselectivity. In contrast to the reaction of (E)-2-alkenyl acetates, the reaction of (Z)-2-alkenyl acetates gave a product alkylated at the unsubstituted allylic terminus predominantly. This shows that the regioselectivity of the alkylation of the syn π-allyl iridium intermediate is different from that of the anti π-allyl iridium intermediate. (Z)- Selective allylic alkylation of (Z)-2-alkenyl esters is also possible by iridium catalysis.
REDUCTION OF α-ALKYNYL EPOXIDES
Vasil'ev, A. A.
, p. 38 - 41 (2007/10/02)
The catalytic hydrogenation of 2-(1-heptynyl)oxirane leads preferentially to 3(Z)-nonen-1-ol, whereas the reduction of this epoxide with lithium in ethylamine gives 3(E)-nonen-1-ol.In both cases the main products are accompanied by the isomeric 2-nonen-1-ols.
COMPOUNDS WITH HERBAL ODOR. V. UNBRANCHED PRIMARY (Z)-ALKENOLS
Vasil'ev, A. A.,Cherkaev, G. V.,Nikitina, M. A.
, p. 735 - 739 (2007/10/02)
The similarity between the odor of alkenols (Z)-CH3-(CH2)n(H=CH(CH2)mOH and the odor of leaf alcohol (m=2, n=1), taken as standard, gradually weakened with change in the m and/or n values and is determined by the number of carbon atoms in the molecules.
