The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Antonio Togni - One of the best experts on this subject based on the ideXlab platform.
-
p stereogenic ferrocene based trifluoromethyl Phosphanes synthesis structure coordination properties and catalysis
European Journal of Organic Chemistry, 2011Co-Authors: Aline Sondenecker, Jan Cvengros, Raphael Aardoom, Antonio TogniAbstract:Diastereoselective ortho-hydroxymethylation of (R)-(1-ferrocenylethyl)dimethylamine and Bronsted-acid-mediated nucleophilic substitution with phenyl(trifluoromethyl)phosphane affords an epimeric mixture of P-stereogenic amine-Phosphanes 4a and 4b, which are readily separated by crystallization from methanol. Subsequent substitution of the dimethylamino group with diphenylphosphane occurs without epimerization, yielding novel bis(Phosphanes) 1a and 1b. These bis(Phosphanes) combine three elements of chirality (C-central, P-central and planar) and bear a trifluoromethyl group at a stereogenic phosphorus atom. Their complexes with transition metals (Pd, Rh, Ir) were studied and characterized by means of NMR techniques and X-ray crystallographic analyses, and the bidentate ligands proved efficient in stereoselective catalysis.
-
P‐Stereogenic Ferrocene‐Based (Trifluoromethyl)Phosphanes: Synthesis, Structure, Coordination Properties and Catalysis
European Journal of Organic Chemistry, 2010Co-Authors: Aline Sondenecker, Jan Cvengros, Raphael Aardoom, Antonio TogniAbstract:Diastereoselective ortho-hydroxymethylation of (R)-(1-ferrocenylethyl)dimethylamine and Bronsted-acid-mediated nucleophilic substitution with phenyl(trifluoromethyl)phosphane affords an epimeric mixture of P-stereogenic amine-Phosphanes 4a and 4b, which are readily separated by crystallization from methanol. Subsequent substitution of the dimethylamino group with diphenylphosphane occurs without epimerization, yielding novel bis(Phosphanes) 1a and 1b. These bis(Phosphanes) combine three elements of chirality (C-central, P-central and planar) and bear a trifluoromethyl group at a stereogenic phosphorus atom. Their complexes with transition metals (Pd, Rh, Ir) were studied and characterized by means of NMR techniques and X-ray crystallographic analyses, and the bidentate ligands proved efficient in stereoselective catalysis.
Declan G Gilheany - One of the best experts on this subject based on the ideXlab platform.
-
a u turn in the asymmetric appel reaction stereospecific reduction of diastereomerically enriched alkoxyphosphonium salts allows the asymmetric synthesis of p stereogenic Phosphanes and phosphane boranes
European Journal of Organic Chemistry, 2012Co-Authors: Kamalraj V Rajendran, Jaya Satyanarayana Kudavalli, Katherine S Dunne, Declan G GilheanyAbstract:An efficient one-pot synthesis has been developed of enantioenriched P-stereogenic Phosphanes and phosphane boranes from the corresponding racemic Phosphanes in excellent yield under asymmetric Appel conditions. The chiral auxiliary (menthol) can also be recovered unchanged. The simple and efficient protocol significantly expands the scope of our asymmetric Appel process. The crucial step in the preparation involves stereospecific reduction of intermediate diastereomeric alkoxyphosphonium salts, which are obtained in the reaction of phosphane, hexachloroacetone, and menthol. Thereby, reaction with LiAlH4 or NaBH4 gives the corresponding Phosphanes or phosphane boranes, respectively.
-
A U‐Turn in the Asymmetric Appel Reaction: Stereospecific Reduction of Diastereomerically Enriched Alkoxyphosphonium Salts Allows the Asymmetric Synthesis of P‐Stereogenic Phosphanes and Phosphane Boranes
European Journal of Organic Chemistry, 2012Co-Authors: Kamalraj V Rajendran, Jaya Satyanarayana Kudavalli, Katherine S Dunne, Declan G GilheanyAbstract:An efficient one-pot synthesis has been developed of enantioenriched P-stereogenic Phosphanes and phosphane boranes from the corresponding racemic Phosphanes in excellent yield under asymmetric Appel conditions. The chiral auxiliary (menthol) can also be recovered unchanged. The simple and efficient protocol significantly expands the scope of our asymmetric Appel process. The crucial step in the preparation involves stereospecific reduction of intermediate diastereomeric alkoxyphosphonium salts, which are obtained in the reaction of phosphane, hexachloroacetone, and menthol. Thereby, reaction with LiAlH4 or NaBH4 gives the corresponding Phosphanes or phosphane boranes, respectively.
Aline Sondenecker - One of the best experts on this subject based on the ideXlab platform.
-
p stereogenic ferrocene based trifluoromethyl Phosphanes synthesis structure coordination properties and catalysis
European Journal of Organic Chemistry, 2011Co-Authors: Aline Sondenecker, Jan Cvengros, Raphael Aardoom, Antonio TogniAbstract:Diastereoselective ortho-hydroxymethylation of (R)-(1-ferrocenylethyl)dimethylamine and Bronsted-acid-mediated nucleophilic substitution with phenyl(trifluoromethyl)phosphane affords an epimeric mixture of P-stereogenic amine-Phosphanes 4a and 4b, which are readily separated by crystallization from methanol. Subsequent substitution of the dimethylamino group with diphenylphosphane occurs without epimerization, yielding novel bis(Phosphanes) 1a and 1b. These bis(Phosphanes) combine three elements of chirality (C-central, P-central and planar) and bear a trifluoromethyl group at a stereogenic phosphorus atom. Their complexes with transition metals (Pd, Rh, Ir) were studied and characterized by means of NMR techniques and X-ray crystallographic analyses, and the bidentate ligands proved efficient in stereoselective catalysis.
-
P‐Stereogenic Ferrocene‐Based (Trifluoromethyl)Phosphanes: Synthesis, Structure, Coordination Properties and Catalysis
European Journal of Organic Chemistry, 2010Co-Authors: Aline Sondenecker, Jan Cvengros, Raphael Aardoom, Antonio TogniAbstract:Diastereoselective ortho-hydroxymethylation of (R)-(1-ferrocenylethyl)dimethylamine and Bronsted-acid-mediated nucleophilic substitution with phenyl(trifluoromethyl)phosphane affords an epimeric mixture of P-stereogenic amine-Phosphanes 4a and 4b, which are readily separated by crystallization from methanol. Subsequent substitution of the dimethylamino group with diphenylphosphane occurs without epimerization, yielding novel bis(Phosphanes) 1a and 1b. These bis(Phosphanes) combine three elements of chirality (C-central, P-central and planar) and bear a trifluoromethyl group at a stereogenic phosphorus atom. Their complexes with transition metals (Pd, Rh, Ir) were studied and characterized by means of NMR techniques and X-ray crystallographic analyses, and the bidentate ligands proved efficient in stereoselective catalysis.
Kamalraj V Rajendran - One of the best experts on this subject based on the ideXlab platform.
-
a u turn in the asymmetric appel reaction stereospecific reduction of diastereomerically enriched alkoxyphosphonium salts allows the asymmetric synthesis of p stereogenic Phosphanes and phosphane boranes
European Journal of Organic Chemistry, 2012Co-Authors: Kamalraj V Rajendran, Jaya Satyanarayana Kudavalli, Katherine S Dunne, Declan G GilheanyAbstract:An efficient one-pot synthesis has been developed of enantioenriched P-stereogenic Phosphanes and phosphane boranes from the corresponding racemic Phosphanes in excellent yield under asymmetric Appel conditions. The chiral auxiliary (menthol) can also be recovered unchanged. The simple and efficient protocol significantly expands the scope of our asymmetric Appel process. The crucial step in the preparation involves stereospecific reduction of intermediate diastereomeric alkoxyphosphonium salts, which are obtained in the reaction of phosphane, hexachloroacetone, and menthol. Thereby, reaction with LiAlH4 or NaBH4 gives the corresponding Phosphanes or phosphane boranes, respectively.
-
A U‐Turn in the Asymmetric Appel Reaction: Stereospecific Reduction of Diastereomerically Enriched Alkoxyphosphonium Salts Allows the Asymmetric Synthesis of P‐Stereogenic Phosphanes and Phosphane Boranes
European Journal of Organic Chemistry, 2012Co-Authors: Kamalraj V Rajendran, Jaya Satyanarayana Kudavalli, Katherine S Dunne, Declan G GilheanyAbstract:An efficient one-pot synthesis has been developed of enantioenriched P-stereogenic Phosphanes and phosphane boranes from the corresponding racemic Phosphanes in excellent yield under asymmetric Appel conditions. The chiral auxiliary (menthol) can also be recovered unchanged. The simple and efficient protocol significantly expands the scope of our asymmetric Appel process. The crucial step in the preparation involves stereospecific reduction of intermediate diastereomeric alkoxyphosphonium salts, which are obtained in the reaction of phosphane, hexachloroacetone, and menthol. Thereby, reaction with LiAlH4 or NaBH4 gives the corresponding Phosphanes or phosphane boranes, respectively.
Tapani A Pakkanen - One of the best experts on this subject based on the ideXlab platform.
-
synthesis characterization reactivity and theoretical studies of ruthenium carbonyl complexes containing ortho substituted triphenyl Phosphanes
Journal of Organometallic Chemistry, 2005Co-Authors: Andreina M Moreno, Matti Haukka, Sirpa Jaaskelainen, Sauli Vuoti, Jouni Pursiainen, Tapani A PakkanenAbstract:Abstract A series of ruthenium o-phosphane complexes was synthesized and characterized. The reactivity of the prepared complexes was studied by using them as catalysts for the hydroformylation of 1-hexene. The activities depended on the binding mode of the phosphane and on the strength of the ruthenium–phosphane interaction. Strongly coordinated chelating [2-(dimethylamino)phenyl]-(diphenyl) phosphane and [2-(methylthio)phenyl]-(diphenyl) phosphane showed poor activity, while weakly chelated [2-(methoxy)phenyl]-(diphenyl) phosphane and non-chelating Phosphanes such as [2-(methyl)phenyl]-(diphenyl) phosphane or [2-(ethyl)phenyl]-(diphenyl) phosphane led to higher activities.