4373-68-6Relevant articles and documents
Quantifying Through-Space Substituent Effects
Adam, Catherine,Burns, Rebecca J.,Cockroft, Scott L.,Mati, Ioulia K.,Muchowska, Kamila B.
supporting information, p. 16717 - 16724 (2020/07/24)
The description of substituents as electron donating or withdrawing leads to a perceived dominance of through-bond influences. The situation is compounded by the challenge of separating through-bond and through-space contributions. Here, we probe the experimental significance of through-space substituent effects in molecular interactions and reaction kinetics. Conformational equilibrium constants were transposed onto the Hammett substituent constant scale revealing dominant through-space substituent effects that cannot be described in classic terms. For example, NO2 groups positioned over a biaryl bond exhibited similar influences as resonant electron donors. Meanwhile, the electro-enhancing influence of OMe/OH groups could be switched off or inverted by conformational twisting. 267 conformational equilibrium constants measured across eleven solvents were found to be better predictors of reaction kinetics than calculated electrostatic potentials, suggesting utility in other contexts and for benchmarking theoretical solvation models.
Palladium dichloride adduct of N,N-bis-(diphenylphosphanylmethyl)-2- aminopyridine: Synthesis, structure and catalytic performance in the decarboxylative cross-coupling of 4-picolinic acid with aryl bromide
He, Run-Tian,Wang, Jian-Feng,Wang, Hui-Fang,Ren, Zhi-Gang,Lang, Jian-Ping
, p. 9786 - 9794 (2014/06/23)
Reaction of PdCl2 with N,N-bis-(diphenylphosphanylmethyl)-2- aminopyridine (bdppmapy) afforded a mononuclear complex [(bdppmapy)PdCl 2] (1). Compound 1 was characterized by elemental analysis, IR, 1H, 13C and 31P NMR, electrospray ion mass spectra (ESI-MS) and X-ray single crystal crystallography. The Pd(ii) center in 1 is chelated by bdppmapy, showing a cis-square planar geometry. With the assistance of additive Cu2O, complex 1 exhibited good catalytic activity toward the decarboxylative cross-coupling reactions between 4-picolinic acid and aryl bromides. In the presence of only 2 mol% catalyst, a family of 4-aryl-pyridines could be isolated in up to 83% yield.
Pyridino-directed lithiation of anisylpyridines: New access to functional pyridylphenols
Parmentier, Micha?l,Gros, Philippe,Fort, Yves
, p. 3261 - 3269 (2007/10/03)
The lithiation of nine anisylpyridines has been studied. While usual reagents did not react or gave addition products on pyridine ring, the BuLi-LiDMAE (LiDMAE=Me2N(CH2)2OLi) superbase induced exclusive pyridino directed metallation. The usefulness of this new reaction allowed the efficient preparation of a range of alpha functional pyridylphenols. A successful subsequent cyclisation of an appropriate isomer into corresponding benzofuropyridine was also performed.
