共查询到20条相似文献,搜索用时 703 毫秒
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Mujahid Mohammad Venkaiah Chintalapudi Jeffrey M. Carney Steven J. Mansfield Pollyanna Sanderson Kirsten E. Christensen Edward A. Anderson 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(50):18345-18349
A highly convergent strategy for the synthesis of the natural product (?)‐rubriflordilactone B, and the proposed structure of (?)‐pseudo‐rubriflordilactone B, is described. Late stage coupling of diynes containing the respective natural product FG rings with a common AB ring aldehyde precedes rhodium‐catalyzed [2+2+2] alkyne cyclotrimerization to form the natural product skeleton, with the syntheses completed in just one further operation. This work resolves the uncertainty surrounding the identity of pseudo‐rubriflordilactone B and provides a robust platform for further synthetic and biological investigations. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(8):2159-2163
Homologation of readily available α‐boryl pyrrolidines with metal carbenoids is especially challenging even when good leaving groups (Cl−) are employed. By performing a solvent switch from Et2O to CHCl3, efficient 1,2‐metalate rearrangement of the intermediate boronate occurs with both halide and ester leaving groups. The methodology was used in the total synthesis of the Stemona alkaloid (−)‐stemaphylline in just 11 steps (longest linear sequence), with high stereocontrol (>20:1 d.r.) and 11 % overall yield. The synthesis also features a late‐stage lithiation–borylation reaction with a tertiary amine containing carbenoid. 相似文献
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Chuan He Jun Xuan Peirong Rao Pei‐Pei Xie Xin Hong Xufeng Lin Hanfeng Ding 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(15):5154-5158
A concise and divergent approach for the total syntheses of four cembrane diterpenoids, namely (+)‐sarcophytin, (+)‐chatancin, (?)‐3‐oxochatancin, and (?)‐pavidolide B, has been developed, and it also led to the structural revision of (?)‐isosarcophytin. The key steps of the strategy feature a double Mukaiyama Michael addition/elimination, a Helquist annulation, two substrate‐controlled facial‐selective hydrations, and a pinacol rearrangement. The described syntheses not only achieved these natural products in an efficient manner, but also provided insight into the biosynthetic relationship between the two different skeletons. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(15):4302-4306
A 3,7‐diazabicyclo[3.3.1]nonane linking to two melamines is a unique transmembrane H+/Cl− carrier. In the solid state, the V‐shaped compound forms a HCl‐bound zig‐zag network through cooperative protonation and hydrogen bond interactions. In the lipid membrane, the receptor forms a dimeric self‐assembly involving multiple H+ and Cl− leading to the efficient transport of the acid. The pH‐dependent Cl− efflux observed for the compound was rationalized based on a gradual protonation model that confers an active transmembrane carrier at physiological pH. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(1):330-333
The first enantioselective total synthesis of (−)‐cycloclavine was accomplished in 8 steps and 7.1 % overall yield. Key features include the first catalytic asymmetric cyclopropanation of allene, mediated by the dirhodium catalyst Rh2(S‐TBPTTL)4, and the enone 1,2‐addition of a new TEMPO carbamate methyl carbanion. An intramolecular strain‐promoted Diels–Alder methylenecyclopropane (IMDAMC) reaction provided a pivotal tricyclic enone intermediate with more than 99 % ee after crystallization. The synthesis of (−)‐ 1 was completed by a late‐stage intramolecular Diels–Alder furan (IMDAF) cycloaddition to install the indole. 相似文献