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Keisuke Nishikawa Kengo Morita Subaru Hashimoto Akihiro Hoshino Takumi Ikeuchi Momochika Kumagai Yoshiki Morimoto 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(30):10274-10278
Biomimetic epoxide‐opening cascades of polyepoxides enable the efficient and rapid construction of polyether frameworks. Herein, we show that the epoxide‐opening cascade cyclization that affords tetrahydrofuran products in acidic aqueous media produces tetrahydropyran (THP) in neutral water. THP formation proceeded by simply heating polyepoxides in neutral water and followed a different cyclization mode from those observed so far. The novel cascade cyclization in H2O was applied to the synthesis of a new nerolidol‐type sesquiterpenoid, resulting in revision of the proposed structure and determination of the absolute configuration. 相似文献
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Jae Hyun Kim Illan Kim Yeonghun Song Min Jung Kim Sanghee Kim 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(32):11134-11138
The total synthesis of (+)‐neooxazolomycin was achieved from the amino‐acid d ‐serine. The efficiency of this approach is derived from the use of principles of memory of chirality and dynamic kinetic resolution in the intramolecular aldol reaction of a serine derivative to build the densely functionalized lactam framework and to install three contiguous stereocenters. The key intermediate was readily elaborated to the target natural product. 相似文献
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Li Zhou Shu‐Yang Yu Yong Tang Lijia Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(42):15158-15162
A highly diastereoselective copper‐catalyzed multicomponent cyclization of exocyclic enol ethers/enamines with methylene malonate and aldehydes has been developed to furnish spiroheterocyclic tetrahydropyrans in high yields with greater than 95:5 d.r. This method is practical, in that 36 examples, including a range of aldehydes and exo‐vinyl heterocycles, are presented. By applying the newly developed method, the total synthesis of (+)‐broussonetine G and formal synthesis of (+)‐broussonetine H were achieved in a concise way. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(4):1107-1111
Stereoselective total syntheses of (−)‐histrionicotoxin and (−)‐histrionicotoxin 235A are described. The 1‐azaspiro[5.5]undecane skeleton was constructed diastereoselectively by a radical translocation–cyclization reaction involving a chiral cyclic acetal; the use of tris(trimethylsilyl)silane was crucial for the high diastereoselectivity. The cyclization product was converted into (−)‐histrionicotoxin 235A through a one‐pot partial‐reduction–allylation reaction of a derivative containing an unprotected lactam. Finally, two terminal alkenes were transformed into enynes with the 1,3‐amino alcohol protected as an oxathiazolidine oxide to complete the total synthesis of (−)‐histrionicotoxin. 相似文献
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