Electrochemical Vicinal Difluorination of Alkenes: Scalable and Amenable to Electron‐Rich Substrates
作者:Sayad Doobary、Alexi T. Sedikides、Henry P. Caldora、Darren L. Poole、Alastair J. J. Lennox
DOI:10.1002/anie.201912119
日期:2020.1.13
oxidative difluorination of alkenes represents an important strategy for their preparation, yet current methods are limited in their alkene-types and tolerance of electron-rich, readily oxidized functionalities, as well as in their safety and scalability. Herein, we report a method for the difluorination of a number of unactivated alkene-types that is tolerant of electron-rich functionality, giving products
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。
Lanthanide(III) Triflate-Catalyzed Thermal- and Microwave-Assisted Synthesis of Benzyl Ethers from Benzyl Alcohols
作者:Anthony Handlon、Yu Guo
DOI:10.1055/s-2004-836063
日期:——
The lanthanide(III) trifluoromethanesulfonate-catalyzed condensation of benzyl alcohols with primary and secondary alcohols is described. This reaction proceeds readily with benzyl alcohols that have an alkyl or aryl substituent at the α-, ortho-, or para-position using microwave radiation or heating. The intramolecular variant of this reaction leads to cyclic benzofurans.
Influence of the −CH<sub>2</sub>X Substituent on the Regioselectivity of Intramolecular <i>meta</i>-Photocycloaddition Reactions
作者:Marcus Wegmann、Thorsten Bach
DOI:10.1021/jo5028613
日期:2015.2.6
In studies related to the synthesis of the bicyclo[3.2.1]octane core of enterocin by an intramolecular meta-photocycloaddition, it was found that the regioselectivity of the reaction depends strongly on the substituent −CH2X in the ortho-position to the tether. Electropositive groups X (X = H, Me, TMS, TES) gave preferentially the linear isomer (regioisomeric ratio = 87/13 to >95/5), whereas electronegative
2-Methylbenzaldehyddialkylacetale der allgemeinen Formel I
in der die Substituenten folgende Bedeutung haben.
R¹C₃- bis C₂₀-Alkyl oder C₁- bis C₁₂-Alkoxy und
R²C₁- bis C₈-Alkyl,
mit der Maßgabe, daß R¹ nicht für Methoxy steht, wenn R² für Methyl steht, sowie deren Herstellung und deren Verwendung zur Herstellung von 2-Methylbenzaldehyden.