The (polyenoyl)tetramicacid militarinone C (1) heads a family of seven members. Before our work, the configuration of C-5 was unknown whereas the configurations of C-8′ and C-10′ were either (R,R) or (S,S). We synthesized the four stereoisomers of constitution 1, which conform with these insights. This included cross-coupling both enantiomers of the western building block (8) with both enantiomers
relative stereochemistry of the β-keto carboxylic acid chain of the analogous alkaloid hirsutellomycin was determined in a stepwise manner. The C4′–C6′ syn relationships were predicted by comparing the NMR data of the corresponding ester fragments with that of hirsutellomycin. The relative stereochemistry of the whole molecule, including the epimerizable C2′ stereocenter, was determined by introduction
Chemoenzymatic Approach to the Total Synthesis of (+)-Bourgeanic Acid
作者:Jhillu Yadav、Tenneti Rao、Nagendra Yadav、Kovvuru Rao、Basi Reddy、Ahmad Al Khazim Al Ghamdi
DOI:10.1055/s-0031-1289699
日期:2012.3
highly stereoselective total synthesis of (+)-bourgeanic acid has been accomplished by an enzymatic desymmetrization approach to create two methyl chiral centers. Other key steps involved in this approach are a Wittig reaction, a Gilman reaction, and TEMPO/iodobenzene diacetate mediated selective oxidation of the 1,3-diol, Yamaguchi lactonization and lithium hydroxide mediated partial hydrolysis (saponification)
A Concise and Efficient Total Synthesis of Militarinone D
作者:Uttam Dash、Sandip Sengupta、Taebo Sim
DOI:10.1002/ejoc.201500380
日期:2015.6
A highly stereoselective, concise (14 steps longest linear sequence and 20 steps overall), and efficient (15 % overall yield) synthesis of militarinone D has been accomplished. The key reactions utilized in the sequence are enzymatic desymmetrization, cis/trans isomerization, Horner–Wadsworth–Emmons olefination, and addition of an organolithium species to a highly conjugated chiral aldehyde. The simplicity
高度立体选择性、简洁(14 步最长的线性序列和 20 步总步)和高效(15% 总产率)的米利他酮 D 合成已经完成。该序列中使用的关键反应是酶促去对称化、顺式/反式异构化、Horner-Wadsworth-Emmons 烯化以及将有机锂物质添加到高度共轭的手性醛中。该策略的简单性使其可用于该目标的大规模生产。此外,用于设计路线的策略应适用于具有各种取代吡啶酮核心结构的类似物的制备。
A Unified Approach for the Stereoselective Total Synthesis of Pyridone Alkaloids and Their Neuritogenic Activity
作者:Henning Jacob Jessen、Andreas Schumacher、Travis Shaw、Andreas Pfaltz、Karl Gademann
DOI:10.1002/anie.201007671
日期:2011.4.26
neurite outgrowth might constitute a valuable approach for the non‐invasive medical treatment of neurodegenerative diseases. With the aid of a bifunctional building block, the total syntheses of a group of pyridone polyenes originally produced by entomopathogenic fungi was achieved (see picture). All of these natural products displayed neuritogenicactivity in the PC‐12 cell line.