Synthesis of a Furanosyl-pyranone Derivative Related to the Tri-O-heterocyclic Core of Herbicidins
作者:Ching-Yun Hsu、I-Chi Lee、Larry S. Lico、Biing-Jiun Uang、Shang-Cheng Hung
DOI:10.1002/jccs.201100744
日期:2012.3
undecose ring structure of herbicidins has been prepared. The synthesis of this novel furanosyl‐pyranone derivative was made possible through the regioselective reductive ring‐opening of a 3,5‐O‐benzylidene‐D‐xylofuranose and the hetero‐Diels—Alderreaction of an aldehyde and a Danishefsky‐type diene. The highly functionalized pyranone derivative can be a useful precursor for the synthesis of herbicidins
dearomatizing [4+2] cycloadditions with silyloxydienes under 16 kbar. Highly functionalized 3-dimensional polycyclic adducts bearing a tetrasubstituted carbon centre at the ring junction are obtained in one step from simple raw materials. This unprecedented dearomative Diels–Alder process is performed at room temperature without any chemical promoter, illustrating the exceptional role of high pressure as a physical
简单的硝基芳烃如硝基萘和硝基喹啉在 16 kbar 下与甲硅烷氧基二烯顺利脱芳构化 [4+2] 环加成反应。从简单的原材料一步即可获得在环连接处带有四取代碳中心的高度功能化的 3 维多环加合物。这种前所未有的去芳烃 Diels-Alder 工艺在室温下进行,没有任何化学促进剂,说明高压作为物理促进剂的特殊作用。
Total Synthesis of Mycinamicin IV as Integral Part of a Collective Approach to Macrolide Antibiotics
作者:Georg Späth、Alois Fürstner
DOI:10.1002/chem.202104400
日期:2022.2.21
Final act: While a “collective” total synthesis of complex macrolide antibiotics illustrates the power of catalysis, it also shows that the glycosylation of elaborate targets remains far from routine. The success critically hinged on the development of robust new approaches to the peripheral (di)deoxy sugars and the proper choice amongst a set of only seemingly equivalent promoters.
developed. The key step is a novel, one-pot, sequential dirhodium(II) tetrakis[(S)-3-(benzo-fused phthalimido)-2-piperidinonate] [Rh 2 (S-BPTPI) 4 ] catalyzed enantioselective hetero-Diels-Alder/TMSOTf-catalyzed Mukaiyama-Michael reaction process. The sign of the optical rotation of natural diospongin B was determined to be (+) and not (-) as was originally reported.
开发了制备二芳基庚烷类二海绵素 A 和 B 的新途径。关键步骤是一种新型的、单锅、连续的二铑 (II) 四[(S)-3-(苯并稠合邻苯二甲酰亚胺)-2-哌啶] [Rh 2 (S-BPTPI) 4 ] 催化的对映选择性杂-Diels -Alder/TMSOTf 催化的 Mukaiyama-Michael 反应过程。天然 diospongin B 的旋光度符号被确定为 (+) 而不是最初报道的 (-)。