total synthesis of the polycyclic polyprenylated acylphloroglucinol (PPAP) natural product hyperforin from 2-methylcyclopent-2-en-1-one is reported. This route was enabled by a diketene annulation reaction and an oxidative ring expansion strategy designed to complement the presumed biosynthesis of this complex meroterpene. The described work enables the preparation of a highly substituted bicyclo[3.3
Additions of structurally diverse α-ketonitriles to aromatic and aliphatic prochiral aldehydes yielding highly enantioenriched acylated cyanohydrins were achieved using a combination of a titanium salen dimer and an achiral or chiral Lewis base. In most cases high yields and high enantioselectivities were observed. The ee was moderate in the initial part of the reaction but increased over time. This
Enantioselective Total Synthesis of (+)‐Garsubellin A
作者:Dongseok Jang、Minchul Choi、Jinglong Chen、Chulbom Lee
DOI:10.1002/anie.202109193
日期:2021.10.11
cyclic molecular architecture, garsubellin A has garnered substantial synthetic interest, but its absolute stereostructure has been undetermined. We report here the first enantioselectivetotalsynthesis of (+)-garsubellin A. Our synthesis relies on stereoselective fashioning of a cyclohexanone framework and double conjugate addition of 1,2-ethanedithiol that promotes aldol cyclization to build the bicyclic
Garsubellin A 是一种能够增强胆碱乙酰转移酶的类萜,人们认为胆碱乙酰转移酶水平的降低在阿尔茨海默病的症状中发挥着重要作用。由于潜在有用的生物活性以及新颖的桥连和稠合环状分子结构,加苏贝林 A 引起了人们的广泛合成兴趣,但其绝对立体结构尚未确定。我们在这里报告了 (+)-garsubellin A 的第一个对映选择性全合成。我们的合成依赖于环己酮框架的立体选择性形成和 1,2-乙二硫醇的双共轭加成,促进羟醛环化以构建双环 [3.3.1] 骨架。十二步无保护基合成路线使得天然 (-)-garsubellin A 及其非天然 (+)-对映体的合成能够用于生物学评价。
Polycyclic Polyprenylated Acylphloroglucinols: An Emerging Class of Non-Peptide-Based MRSA- and VRE-Active Antibiotics
In the past 20 years, peptide‐based antibiotics, such as vancomycin, teicoplanin, and daptomycin, have often been considered as second‐line antibiotics. However, in recent years, an increasing number of reports on vancomycin resistance in pathogens appeared, which forces researchers to find novel lead structures for potent new antibiotics. Herein, we report the total synthesis of a defined endo‐type B
Synthesis of α-aminoketones via selective reduction of acyl cyanides
作者:Andreas Pfaltz、Saeed Anwar
DOI:10.1016/s0040-4039(01)81341-1
日期:1984.1
Reduction of acyl cyanides with zinc in acetic acid in the presence of excess acetic anhydride leads to N-acetyl-α-aminoketones in good yields. An efficient three-step synthesis of 5-aminolevulinic acid by this method is described.