12116-44-8Relevant articles and documents
Tuning reactivity and site selectivity of simple arenes in C-H activation: Ortho-arylation of anisoles via arene-metal π-Complexation
Ricci, Paolo,Kr?mer, Katrina,Larrosa, Igor
, p. 18082 - 18086 (2014)
Current approaches to achieve site selectivity in the C-H activation of arenes involve the use of directing groups or highly electron-poor arenes. In contrast, simple arenes, such as anisole, are characterized by poor reactivity and selectivity. We report
Synthesis and properties of Fischer carbene complexes of N,N-dimethylaniline and anisole π-coordinated to chromium tricarbonyl
Weststrate, Nora-ann,Bouwer, Shalane,Hassenrück, Christopher,van Jaarsveld, Nina A.,Liles, David C.,Winter, Rainer F.,Lotz, Simon
, p. 54 - 66 (2018)
The reaction of lithiated N,N-dimethylaniline π-coordinated to Cr(CO)3 with W(CO)6 and alkylation with [Et3O][BF4] afforded the o-, m- and p-isomers of the σ,π-bimetallic complexes {η6-Me2NC6H4C(OEt)W(CO)5}Cr(CO)3 (o-, 1, m-, 2 and p-isomer, 3). A by-product of the reaction is found by the substitution of a carbonyl ligand in 1 by the aniline nitrogen atom to give {η6-C,N-o-Me2NC6H4C(OEt)W(CO)4}Cr(CO)3 (4). As a result, the W-chelate ring dominates the HOMO rather than the{η6-arene Cr(CO)3} fragment, affecting the site of the first oxidation. Enhanced activation of anisole by π-coordination to Cr(CO)3, and subsequent reactions with nBuLi, W(CO)6 and [Et3O][BF4] gave only o-substituted products {μ,η6:1-o-MeOC6H4C(OEt)W(CO)5}Cr(CO)3 (5), the monocarbene chelate {μ,η6:2-C,O-o-MeOC6H4C(OEt)W(CO)4}Cr(CO)3 (6) by carbonyl substitution, and by reaction of two molar equivalents of these reagents, the unique σ,π-heterotrimetallic biscarbene complex {μ3,η6:1:1-o,o-MeOC6H3(C(OEt)W(CO)5)2}Cr(CO)3 (7). Attempts to synthesise the m- and p-isomers of 5 were unsuccessful due to transmetallation of the lithiated precursors. NMR data confirmed that lithiation and subsequent reactions of m- or p-bromoanisole chromiumtricarbonyl afforded only the o-isomer 5 and {η6-MeOC6H5}Cr(CO)3. Crystal structure determinations of complexes 1–7 confirmed their molecular structures. Spectroscopic data, electrochemistry studies and DFT calculations of the complexes are reported and are in line with a shifting of the HOMO from the Cr(CO)3 to the W(CO)4 chelate entity and with an unusually large delocalization of the HOMO of the other complexes onto the π-coordinated arene ligand and the carbene-bonded metal atom.
Intramolecular CO ... H interaction in Arene(tricarbonyl)-chromium complexes
Bodrikov,Grinval'D,Artemov,Bazhan,Kalagaev, I. Yu.
, p. 20 - 22 (2010)
Unlike benzene(tricarbonyl)chromium which displays two carbonyl stretching vibrations bands in the IR spectrum, analogous tricarbonylchromium complexes of the general formula (C6H5ZMe)Cr(CO)3 [Z = O, CH(OH), N(Pr), CH=CH]
Probing "microwave effects" using Raman spectroscopy
Schmink, Jason R.,Leadbeater, Nicholas E.
, p. 3842 - 3846 (2009)
The use of in situ Raman spectroscopy is reported as a tool for probing the effects of microwave irradiation on molecules. Our results show no evidence for localized superheating, an often-cited specific microwave effect. While the microwave energy may in
ortho-Directing Chromium Arene Complexes as Efficient Mediators for Enantiospecific C(sp2)–C(sp3) Cross-Coupling Reactions
Bigler, Raphael,Aggarwal, Varinder K.
, p. 1082 - 1086 (2018)
A new strategy for the coupling of a broad scope of electronically diverse aromatics to boronic esters is reported. The coupling sequence, which relies on the directed ortho-lithiation of chromium arene complexes followed by boronate formation and oxidation, occurs with complete ortho-selectivity and enantiospecificity to give the coupling products in excellent yields and with high functional group tolerance. An intermediate chromium arene boronate complex was characterized by X-ray, NMR, and IR experiments to elucidate the reaction mechanism.
