In 2016,Knorr, Rudolf; Lattke, Ernst; Ruhdorfer, Jakob; von Roman, Ulrich; Firl, Joachim; Boehrer, Petra published 《What can 13C and 1H NMR lithiation shifts tell us about the charge distribution in α-arylvinyllithium compounds?》.Journal of Organometallic Chemistry published the findings.Application of 7073-94-1 The information in the text is summarized as follows:
The energetically stabilizing delocalization of neg. elec. charge from the Li-C(α) bond into the aryl π system of α-arylvinyllithiums, Ar-C(Li)=CH2, is most efficient with an orthogonal relationship of the aryl ring plane and the C=C double-bond plane. This aryl conformation remains favored with at least one ortho-substituent in the α-aryl group. The lithiation NMR shifts, Δδ = δ(R-Li) – δ(R-H), of the remote, para-positioned 13C and 1H nuclei appear to be dominated by the delocalized π charge (quasi-benzyllithium), as judged through comparison of the C-para/para-H lithiation shift quotients with that of benzyllithium. The magnitudes |Δδ(C-para)| observed with two α-(2-alkylphenyl)vinyllithiums are highest for the trisolvated monomers in THF and decrease with decreasing solvation and increasing aggregation. In 3-lithio-1,1-dimethylindene, on the other hand, the α-aryl group is conformationally fixed in a coplanar relationship with the C=C double bond; this prevents a direct π charge delocalization from the Li-C(α) bond into the adjacent aryl ring with the expected result of Δδ(C-para) ≈ 0 in the absence of electron donor ligands. However, the disolvated dimer of this conformationally flattened α-arylvinyllithium exhibited a Δδ(C-para) value whose magnitude was reduced by only 51% from that of the disolvated dimer of the above α-(2-methylphenyl)vinyllithium with its orthogonal orientation. The experimental part of the paper was very detailed, including the reaction process of 1-Bromo-2-isopropylbenzene(cas: 7073-94-1Application of 7073-94-1)
1-Bromo-2-isopropylbenzene(cas: 7073-94-1) belongs to organobromine compounds.Depending on the type of carbon to which the bromine is bonded, organic bromide could be alkyl, alkenyl, alkynyl, or aryl. Application of 7073-94-1 Due to the reactivity of bromide, they are used as potential precursors or important intermediates in organic synthesis.
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary