Flow electrochemistry: a safe tool for fluorine chemistry
作者:Bethan Winterson、Tim Rennigholtz、Thomas Wirth
DOI:10.1039/d1sc02123k
日期:——
The heightened activity of compounds containing fluorine, especially in the field of pharmaceuticals, provides major impetus for the development of new fluorination procedures. A scalable, versatile, and safe electrochemical fluorination protocol is conferred. The strategy proceeds through a transient (difluoroiodo)arene, generated by anodic oxidation of an iodoarene mediator. Even the isolation of
含氟化合物的活性增强,特别是在制药领域,为新氟化工艺的开发提供了主要动力。提供了一种可扩展、通用且安全的电化学氟化方案。该策略通过碘芳烃介体的阳极氧化产生瞬态(二氟碘)芳烃来进行。甚至二氟化碘( III )的分离也很容易,因为电解是在没有其他试剂的情况下进行的。通过将电解步骤与流动中的下游反应耦合,以高产率实现了广泛的高价碘介导的反应,超越了间歇化学的限制。(二氟碘)芳烃有毒且化学不稳定,因此不间断生成和立即流动使用非常有利。高流速使生产率高达 834 mg h -1,同时大大缩短了反应时间。集成到全自动机器和在线淬火是减少氢氟酸使用带来的危害的关键。
Methyl NFSI: atom-economical alternative to NFSI shows higher fluorination reactivity under Lewis acid-catalysis and non-catalysis
A fast and highly enantioselectivefluorination of [small beta]-keto esters catalyzed by diphenylamine linked bis(oxazoline)-Cu(OTf)2 complexes under solvent-free conditions has been developed using a planetary ball mill.
Enantioselective Fluorination of β-Ketoesters Catalyzed by Chiral Sodium Phosphate: Remarkable Enhancement of Reactivity by Simultaneous Utilization of Metal Enolate and Metal Phosphate
作者:Keiji Mori、Ayaka Miyake、Takahiko Akiyama
DOI:10.1246/cl.130934
日期:2014.1.5
A highly enantioselective fluorination of β-ketoesters catalyzed by chiral sodium phosphate is achieved. In this process, the simultaneous formation of sodium enolate and sodium phosphate under basic conditions is the key to achieving excellent selectivity. Indanone derivatives as well as benzofuranone derivatives could be employed in this reaction to afford the fluorinated adducts in good yields with good to excellent enantioselectivities.
Bifunctional chiral thioureas have been successfully used as organocatalysts in enantioselectivefluorinations of β-ketoesters. The corresponding products could be obtained with good to excellent enantioselectivity in high yields by using N-fluorobisbenzenesulphonimide (NFSI) as fluorination reagent.