Search results for "Carbon–carbon bond"
showing 6 items of 6 documents
A theoretical study of carbon-carbon bond formation by a Michael-type addition.
2012
A theoretical study of the Michael-type addition of 1,3-dicarbonyl compounds to α,β-unsaturated carbonyl compounds has been performed in the gas phase by means of the AM1 semiempirical method and by density functional theory (DFT) calculations within the B3LYP and M06-2X hybrid functionals. A molecular model has been selected to mimic the role of a base, which is traditionally used as a catalyst in Michael reactions, an acetate moiety to modulate its basicity, and point charges to imitate the stabilization of the negative charge developed in the substrate during the reaction when taking place in enzymatic environments. Results of the study of six different reactions obtained at the three di…
Sustainable carbon–carbon bond formation catalyzed by new oxamate-containing palladium(II) complexes in ionic liquids
2013
Abstract New and versatile bis(oxamato)palladate(II) complexes of formula ( n -Bu 4 N) 2 [Pd(2-Mepma) 2 ]·4H 2 O ( 1a ) and ( n -Bu 4 N) 2 [Pd(4-Mepma) 2 ]·2H 2 O·MeCN ( 1b ) ( n -Bu 4 N + = tetra- n -buthylammonium, 2-Mepma = N -2-methylphenyloxamate and 4-Mepma = N -4-methylphenyloxamate) have been synthesized and characterized by spectroscopic methods and single crystal X-ray diffraction. Each palladium(II) ion in 1a and 1b is four-coordinate with two oxygen and two nitrogen atoms from two fully deprotonated oxamate ligands building a centrosymmetric square planar surrounding. Their catalytic role has been investigated for both Heck and Suzuki coupling reactions using a series of aryl…
Molecular Recognition-Induced Function and Competitive Replacement by Hydrogen-Bonding Interactions: Amphiphilic Barbituric Acid Derivatives, 2,4,6-…
1998
The phenomenon of molecular recognition inducing further function is common in nature. However, there are few synthetic systems which achieve this cascade type mechanism, and those are generally ca...
Chemistry and reactivity of mononuclear manganese oxamate complexes: Oxidative carbon-carbon bond cleavage of vic-diols by dioxygen and aldehydes cat…
2006
[EN] Two new mononuclear octahedral manganese(III) complexes with the tetradentate equatorial ligand o-phenylenebis(oxamate) (opba) and two aquo (1a) or two pyridine (1b) axial ligands have been synthesized and characterized structurally, magnetically, and electrochemically. The cyclovoltammogram of 1a in acetonitrile (25 degrees C, 0.1 M Bu4NPF6) shows an irreversible one-electron oxidation peak at a high anodic potential (E-ap = 1.03 V versus SCE), while that of 1b shows two well-separated one-electron oxidation peaks at moderate to high anodic potentials (E-ap = 0.92 and 1.27 V versus SCE), the first redox-wave being quasireversible in nature. The access to formally high-valent Mn-IV and…
Manganese(III)-mediated oxidative carbon-carbon bond cleavage of the 1,10-phenanthroline-5,6-dione ligand
1999
[EN] A new manganese(III)-1,10-phenanthroline-5,6-dione (phendione) complex possessing a putative Mn-2(mu-O) (mu-O2CMe)(2) core has been found to undergo a Ligand-based oxidative cleavage of the C(5)-C(6) bond in weak acid aqueous MeOH under aerobic conditions at room temperature to yield 2,2'-bipyridyl-3,3'-dicarboxylate with co-reduction to the corresponding Mn-II-phendione species.
ChemInform Abstract: Sustainable Carbon-Carbon Bond Formation Catalyzed by New Oxamate-Containing Palladium(II) Complexes in Ionic Liquids.
2014
New and versatile bis(oxamato)palladate(II) complexes (I) are synthesized and investigated for both Suzuki and Heck coupling reactions in molten tetra-n-butylammonium bromide as ionic liquid.