Direct Nucleophilic Difluoromethylation of Carbonyl Compounds
作者:Zuyong Deng、Jin-Hong Lin、Ji Cai、Ji-Chang Xiao
DOI:10.1021/acs.orglett.6b01425
日期:2016.7.1
Phosphonium salt ([Ph3P+CF2H] Br–, DFPB) was found to be an efficient nucleophilic difluoromethylation reagent. Although DFPB is known as a phosphonium ylide precursor, its reaction with carbonylcompounds under traditional “Wittig reaction conditions” did not give the expected Wittig difluoroolefinated products, but afforded the nucleophilic difluoromethylation products, α-CF2H alcohols. Mechanistic
Reaction of the Ruppert–Prakash reagent (Me3SiCF3) with aromatic aldehydes in the presence of triphenylphosphine, lithium iodide and lithium tetrafluoroborate selectively furnishes gem-difluorinated phosphonium salts. Simple alkaline hydrolysis of these salts results in difluoromethylated products. Thus, one-pot nucleophilic difluoromethylation of aromatic aldehydes using Me3SiCF3 has been accomplished
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