Diastereoselective synthesis of protected syn 1,3-diols by base-catalyzed intramolecular conjugate addition of hemiacetal-derived alkoxide nucleophiles
摘要:
Reaction of the illustrated unsaturated hydroxy esters (X = OMe, R2 = H, Me) and amides (X = N(Me)OMe, R2 = H, Me) with benzaldehyde and potassium alkoxide or amide bases is reported. The resulting benzylidene acetals are obtained in good yields (71-84%) and with high selectivity (>90: 10). In addition to an exploration of the scope of the reaction, a mechanistic study, involving the use of deuterated benzaldehyde to ascertain the rate-determining step of the process, is described.
Modular, Scalable Synthesis of Group A Streptogramin Antibiotics
作者:Qi Li、Ian B. Seiple
DOI:10.1021/jacs.7b08577
日期:2017.9.27
synthesis of group A streptogramin antibiotics that proceeds in 6–8 linear steps from simple chemical building blocks. We have applied our route to the synthesis of four natural products in this class including two that have never before been accessed by fully synthetic routes. We anticipate that this work will lead to the discovery of new streptogramin antibiotics that overcome previous limitations of the
Synthetic group A streptogramin antibiotics that overcome Vat resistance
作者:Qi Li、Jenna Pellegrino、D. John Lee、Arthur A. Tran、Hector A. Chaires、Ruoxi Wang、Jesslyn E. Park、Kaijie Ji、David Chow、Na Zhang、Axel F. Brilot、Justin T. Biel、Gydo van Zundert、Kenneth Borrelli、Dean Shinabarger、Cindy Wolfe、Beverly Murray、Matthew P. Jacobson、Estelle Mühle、Olivier Chesneau、James S. Fraser、Ian B. Seiple
DOI:10.1038/s41586-020-2761-3
日期:2020.10.1
group A streptogramins, analogues that overcome the resistance conferred by Vat enzymes have not been previously developed 2 . Here we report the design, synthesis, and antibacterialevaluation of group A streptogramin antibiotics with extensive structural variability. Using cryo-electron microscopy and forcefield-based refinement, we characterize the binding of eight analogues to the bacterial ribosome
天然产物可作为临床使用的大多数抗生素的化学蓝图。这些分子产生的进化过程本质上伴随着抗性机制的共同进化,这些机制会缩短任何给定类别的抗生素 1 的临床寿命。维吉尼亚霉素乙酰转移酶 (Vat) 酶是抗性蛋白,可提供抗链菌素 2 的保护作用,这是一种针对革兰氏阳性菌的强效抗生素,可抑制细菌核糖体 3 。由于选择性地修饰 A 组链菌素的化学复杂的 23 元大环支架的挑战,克服 Vat 酶赋予的抗性的类似物以前尚未开发 2。在这里,我们报告设计,合成,和具有广泛结构变异性的 A 组链霉素抗生素的抗菌评价。使用低温电子显微镜和基于力场的细化,我们以高分辨率表征了八种类似物与细菌核糖体的结合,揭示了延伸到肽基 tRNA 结合位点和占据新生肽出口通道的协同粘合剂的结合相互作用。其中一种类似物对几种金黄色葡萄球菌抗链阳菌素菌株具有优异的活性,在体外表现出降低的乙酰化率,并且在降低感染小鼠模型中的细菌负荷方面
A concise route to virginiamycin M2
作者:Qi Li、Ian B. Seiple
DOI:10.1016/j.tet.2019.04.060
日期:2019.6
Modular, fully synthetic routes to structurally complex natural products provide useful avenues to access chemical diversity. Herein we report a conciseroute to virginiamycin M2, a member of the group A streptogramin class of natural products that inhibits bacterial protein synthesis. Our approach features a longest linear sequence of six steps from 7 simple building blocks, and is the shortest and
Vinylogous Aldol Products from Chiral Crotylsilanes Obtained by Enantioselective Rh(II) and Cu(I) Carbenoid Si−H Insertion
作者:Jie Wu、Yu Chen、James S. Panek
DOI:10.1021/ol100604m
日期:2010.5.7
Enantioenriched homoallylic ethers containing a alpha,beta-unsaturated ester (syn-vinylogous aldol products) were directly accessed by Lewis acid catalyzed crotylation utilizing chiral silane 2. The reagents were prepared by enantioselective Si-H Insertion to an alpha-diazovinylacetates using Davies' Rh-2(DOSP)(4) catalyst or chiral Cu(I) Schiff base complex.
Evans David A., Gauchet-Prunet Joelle A., J. Org. Chem., 58 (1993) N 9, S 2446-2453