86462-75-1Relevant academic research and scientific papers
The Formosalides: Structure Determination by Total Synthesis
Schulthoff, Saskia,Hamilton, James Y.,Heinrich, Marc,Kwon, Yonghoon,Wirtz, Conny,Fürstner, Alois
, p. 446 - 454 (2021)
Total synthesis allowed the constitution of the cytotoxic marine macrolides of the formosalide family to be confirmed and their previously unknown stereostructure to be assigned with confidence. The underlying blueprint was inherently modular to ensure that each conceivable isomer could be reached. This flexibility derived from the use of strictly catalyst controlled transformations to set the stereocenters, except for the anomeric position, which is under thermodynamic control; as an extra safety measure, all stereogenic centers were set prior to ring closure to preclude any interference of the conformation adopted by the macrolactone rings of the different diastereomers. Late-stage macrocyclization by ring-closing alkyne metathesis was followed by a platinum-catalyzed transannular 6-exo-dig hydroalkoxylation/ketalization to craft the polycyclic frame. The side chain featuring a very labile unsaturation pattern was finally attached to the core by Stille coupling.
A Migratory Ether Formation Route to Medium-Sized Sugar Mimetics
Jiang, Hao,Xu, Li-Ping,Fang, Yan,Zhang, Zhen-Xing,Yang, Zhen,Huang, Yong
, p. 14340 - 14344 (2016)
Polyol-substituted cyclic ethers are fundamental building blocks of biomolecules. The position and stereochemistry of multiple hydroxy substituents of cyclic ethers play a central role in their biological function. Current methods for the synthesis of such structures are limited to “naked” ring products with no or few substituents. Here we describe a general route to medium-sized polyol cyclic ethers using a migratory ether formation strategy. In contrast to the common pathway of direct opening of epoxides, Me3Al was found to promote an unprecedented ether addition reaction, opening a neighboring epoxide. The resulting oxonium intermediate triggers a 1,3-methyl shift to yield 2-deoxyribital products. When the hemiacetal auxiliary is a monosaccharide, the sugar ring is expanded by four atoms to give the corresponding 9- to 11-membered analogues. This method provides an entry into the untapped chemical space of medium-sized sugar mimetics.
Mechanistic Details of Asymmetric Bromocyclization with BINAP Monoxide: Identification of Chiral Proton-Bridged Bisphosphine Oxide Complex and Its Application to Parallel Kinetic Resolution
Hamashima, Yoshitaka,Hirokawa, Ryo,Hisanaga, Tatsunari,Ichikawa, Mamoru,Kawato, Yuji,Nagao, Yoshihiro,Takita, Ryo,Watanabe, Kohei,Yamashita, Kenji
, p. 3913 - 3924 (2022/03/15)
The mechanism of our previously reported catalytic asymmetric bromocyclization reactions using 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) monoxide was examined in detail by the means of control experiments, NMR studies, X-ray structure analysis, and CryoSpray electrospray ionization mass spectrometry (ESI-MS) analysis. The chiral BINAP monoxide was transformed to a key catalyst precursor, proton-bridged bisphosphine oxide complex (POHOP·Br), in the presence of N-bromosuccinimide (NBS) and contaminating water. The thus-formed POHOP further reacts with NBS to afford BINAP dioxide and molecular bromine (Br2) simultaneously in equimolar amounts. While the resulting Br2 is activated by NBS to form a more reactive brominating reagent (Br2─NBS), BINAP dioxide serves as a bifunctional catalyst, acting as both a Lewis base that reacts with Br2─NBS to form a chiral brominating agent (P═O+─Br) and also as a Br?nsted base for the activation of the substrate. By taking advantage of this novel concerted Lewis/Br?nsted base catalysis by BINAP dioxide, we achieved the first regio- and chemodivergent parallel kinetic resolutions (PKRs) of racemic unsymmetrical bisallylic amides via bromocyclization.
Probing the Ca2+ mobilizing properties on primary cortical neurons of a new stable cADPR mimic
D'Errico, Stefano,Greco, Francesca,Patrizia Falanga, Andrea,Tedeschi, Valentina,Piccialli, Ilaria,Marzano, Maria,Terracciano, Monica,Secondo, Agnese,Roviello, Giovanni Nicola,Oliviero, Giorgia,Borbone, Nicola
, (2021/10/19)
Cyclic adenosine diphosphate ribose (cADPR) is a second messenger involved in the Ca2+ homeostasis. Its chemical instability prompted researchers to tune point by point its structure, obtaining stable analogues featuring interesting biological properties. One of the most challenging derivatives is the cyclic inosine diphosphate ribose (cIDPR), in which the hypoxanthine isosterically replaces the adenine. As our research focuses on the synthesis of N1 substituted inosines, in the last few years we have produced new flexible cIDPR analogues, where the northern ribose has been replaced by alkyl chains. Interestingly, some of them mobilized Ca2+ ions in PC12 cells. To extend our SAR studies, herein we report on the synthesis of a new stable cIDPR derivative which contains the 2″S,3″R dihydroxypentyl chain instead of the northern ribose. Interestingly, the new cyclic derivative and its open precursor induced an increase in intracellular calcium concentration ([Ca2+]i) with the same efficacy of the endogenous cADPR in rat primary cortical neurons.
Fischer Carbene Pentannulation with Alkynes Having Adjacent Carbonate or Acyloxy Groups: Synthesis of 3-Substituted 1-Indanones
Bhattacharyya, Shubhankar,Chavan, Vijay P.,Fernandes, Rodney A.,Gholap, Sachin P.,Saiyed, Akeel S.
, p. 3438 - 3443 (2020/04/20)
Various aryl Fischer carbenes reacted with alkynes having adjacent acyloxy or carbonate groups to regioselectively deliver 3-substituted 1-indanones. The acyloxy or carbonate group probably coordinates with the Cr metal to give a tetra-coordinated chromium complex forming a six-membered ring that retards CO insertion for ketene formation, which is required for benzannulation. Alternatively, the ortho position aryl ring attack results in pentannulation, providing regioselectively 3-substituted 1-indanones. The method is extended to the synthesis of the core structure of 3-epi-mutisianthol.
Ascaroside Signaling in the Bacterivorous Nematode Caenorhabditis remanei Encodes the Growth Phase of Its Bacterial Food Source
Dolke, Franziska,Dong, Chuanfu,Bandi, Siva,Paetz, Christian,Glauser, Gaétan,Von Reu?, Stephan H.
supporting information, p. 5832 - 5837 (2019/08/26)
A novel class of species-specific modular ascarosides that integrate additional fatty acid building blocks was characterized in the nematode Caenorhabditis remanei using a combination of HPLC-ESI-(-)-MS/MS precursor ion scanning, microreactions, HR-MS/MS, MSn, and NMR techniques. The structure of the dominating component carrying a cyclopropyl fatty acid moiety was established by total synthesis. Biogenesis of this female-produced male attractant depends on cyclopropyl fatty acid synthase (cfa), which is expressed in bacteria upon entering their stationary phase.
Synthesis of Cyclopropane Fatty Acids by C(sp3)?C(sp3) Cross-Coupling Reaction and Formal Synthesis of α-Mycolic Acid
Iwasaki, Takanori,Terahigashi, Shohei,Wang, Yufei,Tanaka, Arisa,Zhao, Hanqing,Fujimoto, Yukari,Fukase, Koichi,Kambe, Nobuaki
supporting information, p. 3810 - 3817 (2018/09/18)
An iterative Ni-catalyzed C(sp3)?C(sp3) cross-coupling reaction of a novel cis-cyclopropane containing bifunctional building blocks with alkyl halides and alkyl Grignard reagents enabled the introduction of a cyclopropane ring into the desired position(s) of saturated carbon frameworks, providing a straightforward synthetic route to cyclopropane fatty acids. The present method creates a direct route for the construction of saturated carbon frameworks, and can avoid the tedious multistep operations based on unsaturated functional group manipulations that are often employed in conventional synthetic routes. This method could be applicable to the synthesis of trans-cyclopropane fatty acids and enantioenriched cyclopropane fatty acids. Formal synthesis of α-mycolic acid was achieved by the C(sp3)?C(sp3) cross-coupling reaction of cyclopropane-containing bifunctional building blocks. (Figure presented.).
Stereoselective Access to the Core Structure of Macroline-Type Indole Alkaloids: Total Synthesis of Macroline and Alstomicine
Kadam, Vilas D.,Rao, Sridhara Shanmukha,Mahesh,Chakraborty, Mithun,Vemulapalli, S. Phani Babu,Dayaka, Satya Narayana,Sudhakar, Gangarajula
supporting information, p. 4782 - 4786 (2018/08/24)
Rapid synthesis of the pentacyclic core structure of macroline-type indole alkaloids, and its application in the total synthesis of macroline and alstomicine is described. The core structure was accomplished in a highly stereocontrolled manner via two key steps, Ireland-Claisen rearrangement and Pictet-Spengler cyclization, commencing from a readily available starting material l-tryptophan, which obviated the need of a particular chiral source as an external catalyst, reagent, or internal auxiliary.
Synthesis and Application of Stereoretentive Ruthenium Catalysts on the Basis of the M7 and the Ru-Benzylidene-Oxazinone Design
Dumas, Adrien,Müller, Daniel S.,Curbet, Idriss,Toupet, Lo?c,Rouen, Mathieu,Baslé, Olivier,Mauduit, Marc
supporting information, p. 829 - 834 (2018/03/21)
A series of new stereoretentive ruthenium catalysts bearing the dithiocatecholate ligand was synthesiszed on the basis of the M7 and Ru-benzylidene-oxazinone design. The activity of the catalysts was tested in ring-opening cross-metathesis reactions, ring
Stereoretentive Olefin Metathesis Made Easy: In Situ Generation of Highly Selective Ruthenium Catalysts from Commercial Starting Materials
Müller, Daniel S.,Curbet, Idriss,Raoul, Yann,Le N?tre, Jér?me,Baslé, Olivier,Mauduit, Marc
supporting information, p. 6822 - 6826 (2018/10/31)
The in situ preparation of highly stereoretentive ruthenium-based metathesis catalysts is reported. This approach completely avoids the isolation of intermediates and air-sensitive catalysts, thus allowing for the rapid access and evaluation of numerous dithiolate Ru catalysts. A procedure was established to perform cross-metathesis reactions without the use of a glovebox, and on a small scale even Schlenk techniques are not required. Consequently, the chemistry displayed in this report is available to every practicing organic chemist and presents a powerful approach for the identification of new stereoretentive catalysts.
