61702-01-0Relevant articles and documents
General C(sp2)-C(sp3) Cross-Electrophile Coupling Reactions Enabled by Overcharge Protection of Homogeneous Electrocatalysts
Hamby, Taylor B.,Sevov, Christo S.,Truesdell, Blaise L.
supporting information, p. 5884 - 5893 (2020/04/10)
Cross-electrophile coupling (XEC) of alkyl and aryl halides promoted by electrochemistry represents an attractive alternative to conventional methods that require stoichiometric quantities of high-energy reductants. Most importantly, electroreduction can readily exceed the reducing potentials of chemical reductants to activate catalysts with improved reactivities and selectivities over conventional systems. This work details the mechanistically-driven development of an electrochemical methodology for XEC that utilizes redox-active shuttles developed by the energy-storage community to protect reactive coupling catalysts from overreduction. The resulting electrocatalytic system is practical, scalable, and broadly applicable to the reductive coupling of a wide range of aryl, heteroaryl, or vinyl bromides with primary or secondary alkyl bromides. The impact of overcharge protection as a strategy for electrosynthetic methodologies is underscored by the dramatic differences in yields from coupling reactions with added redox shuttles (generally >80%) and those without (generally 20%). In addition to excellent yields for a wide range of substrates, reactions protected from overreduction can be performed at high currents and on multigram scales.
Spin Crossover and Valence Tautomerism in Neutral Homoleptic Iron Complexes of Bis(pyridylimino)isoindolines
Scheja, Anne,Baabe, Dirk,Menzel, Dirk,Pietzonka, Clemens,Schweyen, Peter,Br?ring, Martin
, p. 14196 - 14204 (2015/09/28)
Homoleptic iron complexes of six bis(pyridylimino)isoindoline (bpi) ligands with different substituents (H, Me, Et, tBu, OMe, NMe2) at the 4-positions of the pyridine moieties have been prepared and studied with regard to temperature-dependent spin and redox states by a combination of 57Fe M?ssbauer spectroscopy, SQUID magnetometry, single-crystal X-ray diffraction analysis, X-band EPR, and 1H NMR spectroscopy. While the H-, methyl-, and ethyl-substituted complexes remain in a pure high-spin state irrespective of the temperature, the 4-tert-butyl-substituted derivative shows spin-crossover behavior. The methoxy- and dimethylamino-substituted compounds were found to easily undergo oxidation. In the crystalline state, valence tautomeric behavior was observed for the methoxy derivative as a thermally activated charge-transfer transition, accompanied by a spin crossover above 200 K. The valence tautomerism leads to a chelate with one of the bpi ligands as a dianion radical L2-. and with an effective spin of S=2.
Metal free direct formation of various substituted pyrido[2′,1′:2,3]imidazo[4,5-c]isoquinolin-5-amines and their further functionalization
Tber,Hiebel,Allouchi,El Hakmaoui,Akssira,Guillaumet,Berteina-Raboin
, p. 35201 - 35210 (2015/05/05)
Original substituted pyrido[2′,1′:2,3]imidazo[4,5-c]isoquinolin-5-amines have been prepared following a Groebke-Blackburn-Bienaymé MCR combined with an N-deprotection and a spontaneous final cyclization step in moderate to good yields. The flexibility of the described method enables the introduction of diverse groups in the 6 and 7 positions on the resulting scaffold using commercially available starting materials. Furthermore, a Buchwald-Hartwig cross coupling with a wide range of aryl and hetaryl halides has been successfully reported using our heterocyclic primary amine derivatives.
Copper complexes of polyfunctional phthalazines. Mononuclear and polynuclear derivatives
Bautista, Dorothy V.,Dewan, John C.,Thompson, Laurence K.
, p. 2583 - 2593 (2007/10/02)
Mononuclear, binuclear, and trinuclear copper(II) complexes of the tetradentate ligands 1,4-di(2'-pyridyl) aminophthalazine (PAP) and 1,4-di(4'-methyl-2'-pyridyl) aminophthalazine (PAP4Me) and binuclear complexes of the tetradentate ligand 1,4-di(6'-methyl-2'-pyridyl) aminophthalazine (PAP6Me) are reported.In a series of binuclear carboxylate derivatives carboxylate bridges exist between copper centres in all cases and in some cases oxygen bridges (hydroxide or methoxide) are indicated.In all other polynuclear derivatives hydroxide bridges are anticipated on the basis of analytical, spectral and magnetic data.The ligands exist as anionic groups in some binuclear carboxylate derivatives while in the other polynuclear systems neutral ligands are found.In reactions in aqueous solution protonated mononuclear derivatives are obtained for both PAP and PAP4Me in cases where solutions of the metal salts are inherently acidic, followed by polynuclear, neutral ligand complexes which form when the pH increases.Mononuclear protonated complexes are not obtained with PAP6Me, where steric factors may prevent the formation of such derivatives.Low magnetic moments (1.1-1.5 BM) are observed for most hydroxy bridged complexes while even lower values (NO3 indicates a triple bridged binuclear structure including a bidentate nitrate bridge and a hydroxide bridge with an oxygen bridge angle of 115.2 deg.
