Trifluoromethylation of Alkyl Radicals in Aqueous Solution
作者:Haigen Shen、Zhonglin Liu、Pei Zhang、Xinqiang Tan、Zhenzhen Zhang、Chaozhong Li
DOI:10.1021/jacs.7b06044
日期:2017.7.26
The copper-mediated trifluoromethylation of alkyl radicals is described. The combination of Et3SiH and K2S2O8 initiates the radical reactions of alkyl bromides or iodides with BPyCu(CF3)3 (BPy = 2,2'-bipyridine) in aqueous acetone at room temperature to afford the corresponding trifluoromethylation products in good yield. The protocol is applicable to various primary and secondary alkyl halides and
Nickel-Catalyzed Reductive Cross-Coupling of Unactivated Alkyl Halides
作者:Xiaolong Yu、Tao Yang、Shulin Wang、Hailiang Xu、Hegui Gong
DOI:10.1021/ol200617f
日期:2011.4.15
Ni-catalyzed reductive approach to the cross-coupling of two unactivated alkyl halides has been successfully developed. The reaction works efficiently for primary and secondary halides, with at least one being bromide. The mildreaction conditions allow for excellent functional group tolerance and provide the C(sp3)−C(sp3) coupling products in moderate to excellent yields.
Nickel-catalyzed cross-coupling of unactivated alkyl halides using bis(pinacolato)diboron as reductant
作者:Hailiang Xu、Chenglong Zhao、Qun Qian、Wei Deng、Hegui Gong
DOI:10.1039/c3sc51098k
日期:——
The use of bis(pinacolato)diboron as the terminal reductant allows the efficient Ni-catalyzed coupling of unactivated secondary and primary alkyl halides, generating the C(sp3)–C(sp3) coupling products in good yields. The mild catalytic conditions display excellent functional group tolerance, and good chemoselectivities which require only 1.5 equiv. of primary bromides for the coupling with secondary bromides. Preliminary mechanistic studies suggest that an in situ organoborane/Suzuki process is not likely. It was identified that the base and ligand have more profound impact on selecting this reductive coupling pathway. The good chemoselectivity appears to be evoked by the formation of Ni–Bpin catalytic intermediates, which demands matched sizes and reactivities of the alkyl halide coupling partners for optimal coupling efficiency.
Nickel-Catalyzed Reductive Coupling of Aryl Halides with Secondary Alkyl Bromides and Allylic Acetate
作者:Shulin Wang、Qun Qian、Hegui Gong
DOI:10.1021/ol3013342
日期:2012.7.6
A room-temperature Ni-catalyzed reductive method for the coupling of aryl bromides with secondaryalkylbromides has been developed, providing C(sp2)–C(sp3) products in good to excellent yields. Slight modification of this protocol allows efficient coupling of activated aryl chlorides with cyclohexyl bromide and aryl bromides with allylic acetate.
Ni-Catalyzed Reductive Allylation of Unactivated Alkyl Halides with Allylic Carbonates
作者:Yijing Dai、Fan Wu、Zhenhua Zang、Hengzhi You、Hegui Gong
DOI:10.1002/chem.201102984
日期:2012.1.16
catalytic Ni species in the presence of an environmentally benign Zn reductant, delivering allylated alkanes (see scheme). This unprecedented approach allowed a variety of unactivated alkylhalides and substituted allyliccarbonates to regioselectively afford E‐alkenes in good to excellent yields.