Development of (Trifluoromethyl)zinc Reagent as Trifluoromethyl Anion and Difluorocarbene Sources
摘要:
The trifluoromethylation of carbonyl compounds is accomplished by the stable (trifluoromethyOzinc reagent generated and then isolated from CF3I and ZnEt2, which can be utilized as a trifluoromethyl anion source (CF3-). The reaction proceeds smoothly with diamine as a ligand and ammonium salt as an initiator, providing the corresponding trifluoromethylated alcohol products. Moreover, the (trifluoromethyl)zinc reagent can also be employed as a difluorocarbene source (:CF2) not only for gem-difluoroolefination of carbonyl compounds with phosphine but also for gem-difluorocyclization of alkenes or alkynes via the thermal decomposition, respectively.
Generation of Carbocations under Photoredox Catalysis: Electrophilic Aromatic Substitution with 1-Fluoroalkylbenzyl Bromides
作者:Cuiwen Kuang、Xin Zhou、Qiqiang Xie、Chuanfa Ni、Yucheng Gu、Jinbo Hu
DOI:10.1021/acs.orglett.0c03258
日期:2020.11.6
to access valuable 1-fluoroalkyl-1,1-biaryl compounds is established under mild conditions. The key to success is the efficient generation of a destabilized benzylic carbocation intermediate via two consecutive single-electron transfer processes by virtue of visible-light photoredox catalysis. This unique activation pattern avoids using strong Lewis acids and high temperatures that are required for
Palladium-Catalyzed Suzuki-Miyaura Cross-Coupling of Secondary α-(Trifluoromethyl)benzyl Tosylates
作者:Marta Brambilla、Matthew Tredwell
DOI:10.1002/anie.201706631
日期:2017.9.18
palladium‐catalyzed C(sp3)−C(sp2) Suzuki–Miyaura cross‐coupling of aryl boronic acids and α‐(trifluoromethyl)benzyl tosylates is reported. A readily available, air‐stable palladium catalyst was employed to access a wide range of functionalized 1,1‐diaryl‐2,2,2‐trifluoroethanes. Enantioenriched α‐(trifluoromethyl)benzyl tosylates were found to undergo cross‐coupling to give the corresponding enantioenriched
Photoredox-Catalyzed Ring-Opening Addition Reaction between Benzyl Bromides and Cyclic Ethers
作者:Jinbo Hu、Cuiwen Kuang、Chuanfa Ni、Yucheng Gu
DOI:10.1055/a-1671-6856
日期:2022.3
A novel nucleophilic reaction between cyclic ethers and benzylbromides is achieved under photoredox catalysis. The reaction proceeds through a single-electron-transfer (SET) pathway rather than a common SN2 mechanism. By two steps of reduction and oxidation, a benzylbromide heterolyzes to give a carbocation and bromide ion under mild conditions, and then a cyclic ether captures both the carbocation
Reactions of Sodium Borohydride in Acidic Media; XV<sup>1</sup>. A Convenient Synthesis of 1,1,1-Trifluoro-2,2-diarylethanes from Arenes and Sodium Borohydride/Trifluoroacetic Acid
作者:Charles F. Nutaitis、Gordon W. Gribble
DOI:10.1055/s-1985-31335
日期:——
NUTAITIS, CH. F.;GRIBBLE, G. W., SYNTHESIS, BRD, 1985, N 8, 756-758