Search results for "Carbanion"

Modular synthesis of tetrasubstituted imidazoles and trisubstituted oxazoles by aldimine cross-coupling.

2008

Photoinduced HS state in the first spin-crossover chain containing a cyanocarbanion as bridging ligand

2009

A new polymeric approach, based on cyanocarbanion ligands, for the design of spin crossover (SCO) compounds led us to the compound [Fe(abpt)2(tcpd)] (1) (tcpd^2 = (C[C(CN)2|3)^2 , abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) which has been characterised as the first SCO molecular chain involving a cyanocarbanion as bridging ligand. Gomez Garcia, Carlos Jose, Carlos.Gomez@uv.es

Organotitanium reagents in organic synthesis a simple means to adjust reactivity and selectivity of carbanions

1982

Synthesis of (–)-(S)-Norlaudanosine, (+)-(R)-O,O-Dimethylcoclaurine, and (+)-(R)-Salsolidine by Alkylation of an α-Aminonitrile

2007

A short asymmetric synthesis of 1-substituted 1,2,3,4-tetrahydroisoquinoline alkaloids by deprotonation of an unprotected α-aminonitrile and alkylation of the resulting carbanion followed by spontaneous elimination of HCN and asymmetric reduction is described. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

A Convenient Generation of Acetic Acid Dianion

2003

The lithium enediolate of acetic acid can be generated efficiently, as a 0.5 M solution in THF, using lithium amides prepared from n-butyllithium in THF and either diethylamine or 1,3,3-trimethyl-6-azabicyclo-(3.2.1)-octane (AZA). Its reaction with carbonyl compounds leads to the corresponding β-hydroxy acids in good to moderate yields. Better yields are usually obtained when these amines are added in sub-stoichiometric amounts. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

One-Pot Synthesis of Polysubstituted Pyrrolidines from Aminonitriles

2005

α-Aminonitriles with a mono- or unsubstituted amino group as well as a-(alkylideneamino)nitriles can be employed as easily accessible α-aminocarbanion equivalents. Their α-deprotonation yields stabilized carbanions, whichundergo smooth 1,4-addition to α,β-unsaturated carbonyl compounds. The resulting δ-ketoα-aminonitriles can be reductively cyclized to form polysubstituted pyrrolidines.

Hepta- and tetra-nuclear copper(II) clusters self-assembled by cyano- and azacyano-carbanions

2015

International audience; Two polynuclear copper(II) complexes with hydroxido-bridging ligands and polycyanide units, [Cu{Cu(tn)}6(μ2-OH)2(μ3-OH)4Cl2](tcm)4Cl2·2H2O (1) and [{Cu(bpy)}4(OH)4(dca)2](dca)2·bpy·2H2O (2) (tn = NH2(CH2)3NH2; tcm− = [C(CN)3]−, bpy = 2,2′-bipyridyl, dca− = [N(CN)2]−) have been prepared by one-pot reactions. The structure of 1 consists of a centrosymmetric heptanuclear ion [Cu{Cu(tn)}6(μ2-OH)2(μ3-OH)4Cl2]6+. The tcm− and the halide anions which appear as counter-ions in the formula unit, play an important role in the stabilization of the complex since the hydrogen bonding between nitrogen atoms of the tcm− anion and halide anions, and hydrogen atoms of the terminal wa…

Stable Carbanions by Quantitative Metalation of Cationically Obtained Diphenylvinyl and Diphenylmethoxy Compounds:  New Initiators for Living Anionic…

1997

Novel Alkylanthracenes Synthesis, Reductive Alkylation, and Reductive Polymerization

1988

A series of novel substituted anthracenes has been prepared which carry two or four n-alkyl groups at C-2 and C-3 (C-6 and C-7). The route taken includes the synthesis of novel 2,3-dialkylbutadienes, their Diels-Alder reaction with 1,4-benzo- or 1,4-naphthoquinone, the dehydrogenation of the adducts, and the reduction of the anthraquinones. The substituted anthracenes are submitted to reduction and reductive alkylation in ethereal solvents and in liquid ammonia to yield 9,10-dialkyl-substituted 9,10-dihydroanthracenes. A modification of the reductive alkylation, i.e. the introduction of 1,n-dihaloalkanes as electrophiles, provides polymeric chains, in which dihydroanthracene moieties are li…

The Reductive σ Bond Cleavage of Barbaralane and 2,6‐Diphenylbarbaralane

1987

Barbaralane (2) and 2,6-diphenylbarbaralane (8) are synthesized in a straightforward way. The reductive cleavage of the strained hydrocarbons is achieved with alkali metals. The structure of the metallation products, in particular the bonding in the resulting allyl moieties, is elucidated by 1H- and 13C-NMR spectroscopy. The chemical behavior (oxidation, protonation, alkylation) sheds light on the modes of stabilization of the alkali metal derivatives. Die reduktive σ-Bindungsspaltung von Barbaralan und 2,6-Diphenylbarbaralan Barbaralan (2) und 2,6-Diphenylbarbaralan (8) werden auf rationelle Weise synthetisiert und die gespannten Kohlenwasserstoffe durch Reaktion mit Alkalimetallen redukti…