1143018-85-2Relevant articles and documents
Nucleophilic Addition and α-C-H Substitution Reactions of an Imine Mediated by Dibutylmagnesium and Organolithium Reagents
Dang, Yan,Jia, Chaohong,Li, Yafei,Li, Yahong,Lu, Yanhua,Wang, Yalan,Xia, Yuanzhi,Xu, Man,Zhang, Liang
, (2021)
A series of nucleophilic addition reactions and α-C-H substitution reactions of an imine-containing ligand 2-(2-((((1H-pyrrol-2-yl)methylene)amino)methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine (HL1) were reported. The reactions of HL1 with 0.5 and 2 equiv ofnBu2Mg, respectively, gave two complexes of compositions [Mg(L1)2] (1) and [Mg2(L2)2] (2) (H2L2 =N-((1-(2-(dimethylamino)ethyl)-1H-pyrrol-2-yl)methyl)-1-(1H-pyrrol-2-yl)pentan-1-amine). The nucleophilic addition ofnBu2Mg to the C═N bond of the HL1 ligand occurred in the process for the formation of2. Treatment of HL1 with 2 and 1 equiv ofnBuLi generated [Li2(L3)2] (3) (HL3 = 2-(2-(((1-(1H-pyrrol-2-yl)pentylidene)amino)methyl)-1H-pyrrol-1-yl)-N,N-dimethylethan-1-amine) and [Li2(L1)2] (4). An α-C-H substitution of the HC═NR moiety of the HL1 ligand triggered bynBuLi was discovered in the preparation of3. The formation of3demonstrates a new concept for the C-C coupling that involved inert C-H bond activation of HC═NR skeleton. The reactions of HL1 with MeLi,sec-BuLi, and tert-BuLi, respectively, were also examined. The products for both the nucleophilic addition of organolithium reagents to the C═N bond and α-C-H substitution of the HC═NR moiety of the HL1 ligand were determined. The mechanisms for the formations of2and3were rationalized by DFT calculations. The hydroboration reactions catalyzed by2were investigated, and these reactions characterize ample substrate scope, very good yields, and high selectivity.
Catalytic Hydroboration of Esters by Versatile Thorium and Uranium Amide Complexes
Makarov, Konstantin,Kaushansky, Alexander,Eisen, Moris S.
, p. 273 - 284 (2022/01/03)
The challenging hydroboration of esters is achieved using simple uranium and thorium amides, U[N(SiMe3)2]3 and [(Me3Si)2N]2An[κ2-(N,C)-CH2Si(CH3)2N(SiMe3)] (An = Th or U) acting as precatalysts in the reaction with pinacolborane (HBpin). All three complexes showed impressive catalytic activities, reaching excellent yields. A large scope of esters was investigated including aliphatic, aromatic, and heterocyclic esters that were transformed cleanly to the corresponding hydroborated alcohols, which readily hydrolyzed to the free alcohols. Moreover, the actinide catalysts demonstrated unexpected high functional tolerance toward nitro, halide, cyano, and heteroaromatic functional groups. The reaction exhibited excellent selectivity toward the ester when additional double and triple unsaturated C-C bonds were present. Lactones and poly caprolactone have been successfully cleaved to the monomeric units, showing a great promise toward polymer degradation and recycling. Detailed kinetic studies are provided in order to determine the rate dependence on the concentration of catalyst, HBpin, and ester. A plausible mechanism is proposed based on stoichiometric reactions, DFT calculations, thermodynamic measurements, and deuterium-labeling studies.
Silver-Catalyzed Hydroboration of C-X (X = C, O, N) Multiple Bonds
Pandey, Vipin K.,Tiwari, Chandra Shekhar,Rit, Arnab
supporting information, p. 1681 - 1686 (2021/03/03)
AgSbF6 was developed as an effective catalyst for the hydroboration of various unsaturated functionalities (nitriles, alkenes, and aldehydes). This atom-economic chemoselective protocol works effectively under low catalyst loading, base- A nd solvent-free moderate conditions. Importantly, this process shows excellent functional group tolerance and compatibility with structurally and electronically diverse substrates (>50 examples). Mechanistic investigations revealed that the reaction proceeds via a radical pathway. Further, the obtained N,N-diborylamines were showcased to be useful precursors for amide synthesis.
