utilization of decomposition products of PFECAs. We report herein a new series of deoxyfluorination reagents featuring OCF2 functional groups derived from certain PFECAs. Alkyl fluorides were generated from various alcohols in ≤97% yield by these novelreagents. The mechanistic experiment verified in situgeneration of carbonic difluoride (COF2).
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.
作者:Yusuke Takahira、Miao Chen、Yu Kawamata、Pavel Mykhailiuk、Hugh Nakamura、Byron K. Peters、Solomon H. Reisberg、Chao Li、Longrui Chen、Tamaki Hoshikawa、Tomoyuki Shibuguchi、Phil S. Baran
DOI:10.1055/s-0037-1611737
日期:2019.6
A simple and robust method for electrochemical alkyl C–H fluorination is presented. Using a simple nitrate additive, a widely available fluorine source (Selectfluor), and carbon-based electrodes, a wide variety of activated and unactivated C–H bonds are converted into their C–F congeners. The scalability of the reaction is also demonstrated with a 100 gram preparation of fluorovaline.
Photoexcited acetophenone can catalyze the fluorination of unactivatedC(sp(3))-H groups. While acetophenone, a colorless oil, only has a trace amount of absorption in the visiblelight region, its photoexcitation can be achieved by irradiation with light generated by a household compact fluorescent lamp (CFL). This operational simple method provides improved substrate scope for the direct incorporation
A group effort: Reported is the title reaction using a polycomponent catalytic system involving commercially available Selectfluor, a putative radical precursor N‐hydroxyphthalimide, an anionic phase‐transfer catalyst (KB(C6F5)4), and a copper(I) bis(imine). The catalyst system formed leads to monofluorinated compounds selectively (see example) without the necessity for an excess of the alkane substrate
共同努力:报告为使用多组分催化体系的标题反应,涉及可商购的Selectfluor,推定的自由基前体N-羟基邻苯二甲酰亚胺,阴离子相转移催化剂(KB(C 6 F 5)4)和铜(I)二(亚胺)。形成的催化剂体系选择性地产生单氟化化合物(参见实施例),而无需过量的烷烃底物。