The synthesis and characterization of a series of structurally varied N-phosphinoamidinate-ligated cobalt complexes is described, along with the successful application of these and a related iron complex as precatalysts in the isomerization hydroboration of terminal, geminal, and internal alkenes. These reactions proceed under mild conditions (23-65 degrees C), at relatively low base-metal loadings (1-5 mol %), typically without cosolvent, and with high terminal hydroboration selectivity across a broad spectrum of branched alkenes. With some of the alkene substrates examined, the Nphosphinoamidinate-ligated precatalysts employed herein are shown to provide alternative terminal selectivity versus other previously reported precatalyst classes for such transformations. Reports of terminal-selective metal-catalyzed alkene isomerization hydroboration disclosed thus far in the literature employ pinacolborane (HBPin); while effective in the system herein, we also report the first examples of such transformations employing either 1,3-dimethyl-1,3-diaza-2-boracydopentane or benzo-1,3,2-diazaborolane. The application of these 1,3,2-diazaborolanes in place of HBPin in some instances enables novel terminal selectivity in the isomerization hydroboration of branched alkenes.
Intramolecular alkene hydroamination and degradation of amidines: divergent behavior of rare earth metal amidinate intermediates
作者:Dexing Zhang、Ruiting Liu、Xigeng Zhou
DOI:10.1039/c8cy01481g
日期:——
and nitriles is also developed. Additionally, amidine reconstruction followed by an intramolecular alkene hydroamidination strategy for the synthesis of substituted imidazolines and tetrahydropyrimidines from secondary enamines and inactive amidines has also been established, which may circumvent the need for some unavailable starting materials. The mechanistic studies prove that these reactions proceed
(<i>N</i>-Phosphinoamidinate)Iron Pre-Catalysts for the Room Temperature Hydrosilylation of Carbonyl Compounds with Broad Substrate Scope at Low Loadings
作者:Adam J. Ruddy、Colin M. Kelly、Sarah M. Crawford、Craig A. Wheaton、Orson L. Sydora、Brooke L. Small、Mark Stradiotto、Laura Turculet
DOI:10.1021/om400883u
日期:2013.10.14
The synthesis and structural characterization of three-coordinate iron(II) and cobalt(II) complexes supported by new N-phosphinoamidinate ligands is reported, along with the successful application of these complexes as precatalysts for the challenging room-temperature hydrosilylation of carbonyl compounds to afford alcohols upon workup. Under the rigorous screening conditions employed (0.015 mol %
Trimethylaluminium-Mediated Reaction of Primary Carboxamides with Amines and Indoles: A Convenient Synthesis of Amidines and Indole-3-acylimines
作者:A. Velavan、S. Sumathi、K. K. Balasubramanian
DOI:10.1002/ejoc.201402386
日期:2014.9
A simple, convenient and generalmethod, exhibiting good functional group tolerance, is described for the synthesis of N- and N,N-disubstituted amidines by the reaction of primary carboxamides with amines mediated by trimethylaluminium (AlMe3). Subsequent reaction of the indole systems with primary carboxamides in the presence of AlMe3 gives exclusively the C-3 substituted imine product.
The present invention includes novel hexadentate metal complexes. The complexes hexadentate ligands of the present invention may be useful as improved emitters in an OLED device.
pattern. Thus, dimeric (1c, 1d, and 1u) and tetrameric (1f) aggregates with strong NH···OC hydrogen bonding, as well as polymeric chain structures (1x and 1z) were observed in the solid state. Furthermore, a dimer 1k involving only the amidine subunits, rather than the carbonyl function, was found. Monolayers of molecules 1u and 1ab physisorbed at the liquid/HOPG (high orientated pyrolytic graphite)