743384-09-0Relevant articles and documents
Rhodium-catalyzed asymmetric hydrogenation of olefins with PhthalaPhos, a new class of chiral supramolecular ligands
Pignataro, Luca,Boghi, Michele,Civera, Monica,Carboni, Stefano,Piarulli, Umberto,Gennari, Cesare
, p. 1383 - 1400 (2012/03/27)
A library of 19 binol-derived chiral monophosphites that contain a phthalic acid diamide group (Phthala- Phos) has been designed and synthesized in four steps. These new ligands were screened in the rhodium-catalyzed enantioselective hydrogenation of prochiral dehydroamino esters and enamides. Several members of the library showed excellent enantioselectivity with methyl 2-acetamido acrylate (6 ligands gave >97% ee), methyl (Z)-2- acetamido cinnamate (6 ligands gave >94% ee), and N-(1-phenylvinyl)acetamide (9 ligands gave >95% ee), whilst only a few representatives afforded high enantioselectivities for challenging and industrially relevant substrates N-(3,4-dihydronaphthalen-1- yl)-acetamide (96% ee in one case) and methyl (E)-2-(acetamidomethyl)-3- phenylacrylate (99% ee in one case). In most cases, the new ligands were more active and more stereoselective than their structurally related monodentate phosphites (which are devoid of functional groups that are capable of hydrogen-bonding interactions). Control experiments and kinetic studies were carried out that allowed us to demonstrate that hydrogen-bonding interactions involving the diamide group of the PhthalaPhos ligands strongly contribute to their outstanding catalytic properties. Computational studies carried out on a rhodium precatalyst and on a conceivable intermediate in the hydrogenation catalytic cycle shed some light on the role played by hydrogen bonding, which is likely to act in a substrate-orientation effect.
SEPIAPTERIN REDUCTASE INHIBITORS FOR THE TREATMENT OF PAIN
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, (2011/05/05)
Disclosed herein are small molecule heterocyclic inhibitors of sepiapterin reductase (SPR), and pro-drugs and pharmaceutically acceptable salts thereof. The Also featured are pharmaceutical compositions of the compounds and uses of these compounds for the treatment or prevention of pain (e.g., inflammatory pain, nociceptive pain, functional pain, and neuropathic pain)
Phthalaphos: Chiral supramolecular ligands for enantioselective rhodium-catalyzed hydrogenation reactions
Pignataro, Luca,Carboni, Stefano,Civera, Monica,Colombo, Raffaele,Piarulli, Umberto,Gennari, Cesare
supporting information; experimental part, p. 6633 - 6637 (2010/10/21)
Interligand hydrogen bonding of chiral monodentate phosphite ligands bearing H-bond donor and acceptor groups leads to formation of supramolecular bidentate ligands, rhodium complexes of which (see picture) afford excellent enantiomeric excesses in catalyzed hydrogenation of classical benchmark and industrially relevant substrates. cod=1,5-cyclooctadiene.
Nucleophilic de-coordination and electrophilic regeneration of "hemilabile" pincer-type complexes: Formation of anionic dialkyl, diaryl, and dihydride PtII complexes bearing no stabilizing π-acceptors
Poverenov, Elena,Gandelman, Mark,Shimon, Linda J. W.,Rozenberg, Haim,Ben-David, Yehoshoa,Milstein, David
, p. 4673 - 4684 (2007/10/03)
Novel anionic dialkyl, diaryl, and dihydride platinum(II) complexes based on the new πlong-armπ hemilabile PCN-type ligand C6H 4[CH2P(tBu)2](CH2) 2N(CH3)2 with the general formula Li + [Pt(PCN)(R)2]- (R = Me (4), Ph (6) and H (9)) were prepared by reaction of [Pt(PCN)(R)] complexes (obtained from the corresponding chlorides) with an equivalent of RLi, as a result of the opening of the chelate ring. Alkylating agents based on other metals produce less stable products. These anionic d8 complexes are thermally stable although they bear no stabilizing π acceptors. They were characterized by 1H, 31P{1H}, 13C, and 7Li NMR spectroscopy; complex 9 was also characterized by single crystal X-ray crystallography, showing that the Li + ion is coordinated to the nitrogen atom of the open amine arm and to the hydride ligand (trans to the P atom) of a neighboring molecule (H-Li = 2.15 A), resulting in a dimeric structure. Complexes 4 and 9 exhibit high nucleophilic reactivity, upon which the pincer complex is regenerated. Reaction of 4 with water, methyl iodide, and iodobenzene resulted in the neutral complex [Pt(PCN)(CH3)] (3) and methane, ethane, or toluene, respectively. Labeling studies indicate that the reaction proceeds by direct electrophilic attack on the metal center, rather than attack on the alkyl ligand. The anionic dihydride complex 9 reacted with water and methyl iodide to yield [Pt(PCN)(H)] (8) and H2 or methane, respectively.