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Synthesis, bridgehead functionalization, and photoisomerization of 9,10-diboratatriptycene dianions
9,10-Diboratatriptycene salts M(2)[RB(μ-C(6)H(4))(3)BR] (R = H, Me; M(+) = Li(+), K(+), [n-Bu(4)N](+)) have been synthesized via [4 + 2] cycloaddition between doubly reduced 9,10-dihydro-9,10-diboraanthracenes M(2)[DBA] and benzyne, generated in situ from C(6)H(5)F and C(6)H(5)Li or LiN(i-Pr)(2). [H...
Autores principales: | , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society of Chemistry
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10207881/ https://www.ncbi.nlm.nih.gov/pubmed/37234897 http://dx.doi.org/10.1039/d3sc00555k |
Sumario: | 9,10-Diboratatriptycene salts M(2)[RB(μ-C(6)H(4))(3)BR] (R = H, Me; M(+) = Li(+), K(+), [n-Bu(4)N](+)) have been synthesized via [4 + 2] cycloaddition between doubly reduced 9,10-dihydro-9,10-diboraanthracenes M(2)[DBA] and benzyne, generated in situ from C(6)H(5)F and C(6)H(5)Li or LiN(i-Pr)(2). [HB(μ-C(6)H(4))(3)BH](2−) reacts with CH(2)Cl(2) to form quantitatively the bridgehead-derivatized [ClB(μ-C(6)H(4))(3)BCl](2−), while twofold H(−) abstraction with B(C(6)F(5))(3) in the presence of SMe(2) leads cleanly to the diadduct (Me(2)S)B(μ-C(6)H(4))(3)B(SMe(2)). Photoisomerization of K(2)[HB(μ-C(6)H(4))(3)BH] (THF, medium-pressure Hg lamp) provides facile access to diborabenzo[a]fluoranthenes, a little explored form of boron-doped polycyclic aromatic hydrocarbons. According to DFT calculations, the underlying reaction mechanism consists of three main steps: (i) photoinduced di-π-borate rearrangement, (ii) “walk reaction” of a BH unit, and (iii) boryl anion-like C–H activation. |
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