A Highly Stereoselective and Practical Total Synthesis of the Tricyclic β-Lactam Antibiotic GV104326 (4-Methoxytrinem)
摘要:
A novel and practical total synthesis of a tricyclic beta-lactam antibiotic, GV104326 (4-methoxytrinem or Sanfetrinem) has been achieved in nine steps and about 33% overall yield from a commercially available acetoxyazetidinone chiron. A key step in the highly diastereoselective synthesis is a protonation of a zinc enolate complex which circumvents the use of enantiomerically pure (S)-2-methoxycyclohexanone. A mechanistic rationale is presented and experimentally verified.
Photoredox-catalyzed deoxyfluorination of activated alcohols with Selectfluor®
作者:María González-Esguevillas、Javier Miró、Jenna L. Jeffrey、David W.C. MacMillan
DOI:10.1016/j.tet.2019.05.043
日期:2019.8
Herein we disclose a deoxyfluorination of alcohols with an electrophilic fluorine source via visible-light photoredox catalysis. This radical-mediated C–F coupling is capable of fluorinating secondary and tertiary alcohols efficiently, complementing previously reported nucleophilic deoxyfluorination protocols.
Fura-2FF-based calcium indicator for protein labeling
作者:Agostina A. Ruggiu、Michael Bannwarth、Kai Johnsson
DOI:10.1039/c000158a
日期:——
We describe the synthesis and fluorescence properties of a Fura-2FF-based fluorescent Ca2+ indicator that can be covalently linked to SNAP-tag fusion proteins and retains its Ca2+ sensing ability after coupling to protein.
Catalytic Phosphorus(V)-Mediated Nucleophilic Substitution Reactions: Development of a Catalytic Appel Reaction
作者:Ross M. Denton、Jie An、Beatrice Adeniran、Alexander J. Blake、William Lewis、Andrew M. Poulton
DOI:10.1021/jo201085r
日期:2011.8.19
from stoichiometric waste products into catalysts and a new concept for catalytic phosphorus-based activation and nucleophilicsubstitution of alcohols has been validated. The present study has focused on a full exploration of the scope and limitations of phosphine oxide catalyzed chlorination reactions as well as the development of the analogous bromination reactions. Further mechanistic studies, including
Synthesis of esters of the potent anti-bacterial trinems and analogues
作者:P. Mark Jackson、Stanley M. Roberts、Silvia Davalli、Daniele Donati、Carla Marchioro、Alcide Perboni、Stefano Proviera、Tino Rossi
DOI:10.1039/p19960002029
日期:——
Coupling the silylenolether 5 and the β-lactam 9(R = Me3Si) affords the ketones 13a–d. Compounds 13a, 13c and 13d are converted into the tricyclic lactams 16–20, 23–25. (Chemoenzymatic synthesis of optically pure silylenolether 5 gave access to homochiral lactams 23–25.) In addition the ketoazetidinones 13 are protected as the 1,3-oxazanes 30. A hydroxyethyl moiety is introduced into these oxazanes
甲硅烷基烯醇醚5和β-内酰胺9(R = Me 3 Si)偶联得到酮13a-d。化合物13a,13c和13d转化为三环内酰胺16-20、23-25。(光学纯的甲硅烷基烯醇醚5的化学酶法合成可得到同手性内酰胺23-25。)此外,酮氮杂环丁酮13被保护为1,3-恶唑烷30。使用Bouffard方法进行所需的立体化学反应,得到醇32。形成相应的碳酸硝基苄酯,脱保护和氧化提供了酮35a和35b,其随后分别转化为三苯甲基41a和41b。
Conversion of Hydroxyl Groups in Alcohols to Other Functional Groups with<i>N</i>-Hydroxy-2-thiopyridone, and Its Application to Dialkylamines and Thiols
作者:Hideo Togo、Misa Fujii、Masataka Yokoyama
DOI:10.1246/bcsj.64.57
日期:1991.1
The radical decarboxylation reaction of N-alkoxyoxalyloxy-2-thiopyridone which was prepared by the reaction of alcohol, oxalyl chloride, and N-hydroxy-2-thiopyridone was studied both in the absence and presence of olefinic compounds. The same reactions with olefinic and acetylenic alcohols gave the corresponding lactone derivatives. On the other hand the unsymmetrical alkyl 2-pyridyl disulfides were obtained by the same reaction with aliphatic thiols.