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Xu‐Wen Li Alexandre Ear Lukas Roger Dr. Nassima Riache Alexandre Deville Dr. Bastien Nay 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(48):16389-16393
A bio‐inspired strategy was used to complete the formal synthesis of the antitubercular hirsutellone B and congeners A and C, through construction of its decahydrofluorene core from a linear polyene strand activated at both ends by a silyl enol ether and an allyl acetate. Our synthesis features a key electrophilic cyclization, starting with the remote activation (by [Yb(OTf)3] or BF3 ? OEt2) of the allyl acetate and stereoselectively affording the C ring. This was followed by an intramolecular Diels–Alder reaction to get the tricyclic core of the natural product. The stereoselective reduction of the resulting ketone towards the formal intermediate was critical to the success of this strategy. 相似文献
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Queueing Systems - We consider strategic arrivals to a FCFS service system that starts service at a fixed time and has to serve a fixed number of customers, for example, an airplane boarding... 相似文献
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Quemet Alexandre Buravand Emilie Peres Jean-Gabriel Dalier Vincent Bejaoui Syriac 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(2):1051-1061
Journal of Radioanalytical and Nuclear Chemistry - This paper details the different steps for the isotopic determination of UAmO2 discs from analytical irradiation. MARIOS and DIAMINO irradiations... 相似文献
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Large‐Scale Synthesis of Enantiopure Molecular Cages: Chiroptical and Recognition Properties
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Sara Lefevre Dawei Zhang Estelle Godart Marion Jean Dr. Nicolas Vanthuyne Jean‐Christophe Mulatier Dr. Jean‐Pierre Dutasta Dr. Laure Guy Prof. Alexandre Martinez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):2068-2074
A convenient and efficient gram‐scale synthesis for enantiopure hemicryptophane–tren (tren=tris(2‐aminoethyl)amine) derivatives has been developed. The four‐step synthesis is based on the optical resolution of a key intermediate, cyclotriveratrylene, for which the energy barrier for racemization has been measured to ensure that no racemization occurs during the two last steps of the synthetic pathway. The assignments of the absolute configurations have been performed by electronic circular dichroism and the enantiopurity was determined by NMR spectroscopy in the presence of enantiopure camphor sulfonic acid. To highlight the interest of such compounds, the recognition of norephedrine neurotransmitter was investigated and showed a remarkable enantioselectivity towards the C3 symmetrical hosts. Finally, this highly modular synthetic pathway was used to provide eight enantiopure hemicryptophanes with different sizes, shapes, and functionalities. These results underline the high potential of this approach, which could lead to many applications in chiral recognition or asymmetric supramolecular catalysis. 相似文献
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