The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Jean-luc Parrain - One of the best experts on this subject based on the ideXlab platform.
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Asymmetric Rhodium-Directed anti-Markovnikov Regioselective Boracyclopentannulation
Journal of the American Chemical Society, 2012Co-Authors: Momar Toure, Olivier Chuzel, Jean-luc ParrainAbstract:A Shimoi-type activation of B−H bond of NHC-Boranes by a diphosphane-ligated cationic Rh complex was applied in an unprecedented intramolecular hydroboration reaction of simple olefins. The use of NHCBoranes as hydroborating reagents is still undisclosed due to their nonreactivity toward alkenes which could be explained by the high stability of this complex rendering it unable to provide a "free" Borane hydroborating reagent. B−H bond Rh activation of NHC-Borane circumvents this limitation, and asymmetric Rh-directed anti-Markovnikov boracyclopentannulation reaction led to a library of enantioenriched cyclic Boranes in high yield (up to 94%) with high regio- (up to 100%) and enantioselectivity (er up to 99.2:0.8). This new activation mode of NHCBoranesn highlights their use in organometallic chemistry and offers a very good approach to access chiral cyclic NHC-Boranes.
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Asymmetric Rhodium-Directed anti-Markovnikov Regioselective Boracyclopentannulation
2012Co-Authors: Momar Toure, Olivier Chuzel, Jean-luc ParrainAbstract:A Shimoi-type activation of B–H bond of NHC-Boranes by a diphosphane-ligated cationic Rh complex was applied in an unprecedented intramolecular hydroboration reaction of simple olefins. The use of NHC-Boranes as hydroborating reagents is still undisclosed due to their nonreactivity toward alkenes which could be explained by the high stability of this complex rendering it unable to provide a “free” Borane hydroborating reagent. B–H bond Rh activation of NHC-Borane circumvents this limitation, and asymmetric Rh-directed anti-Markovnikov boracyclopentannulation reaction led to a library of enantioenriched cyclic Boranes in high yield (up to 94%) with high regio- (up to 100%) and enantioselectivity (er up to 99.2:0.8). This new activation mode of NHC-Boranes highlights their use in organometallic chemistry and offers a very good approach to access chiral cyclic NHC-Boranes
Michal K Pietrusiewicz - One of the best experts on this subject based on the ideXlab platform.
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the synthesis and reactivity of phosphinous acid Boranes
Synthesis, 2005Co-Authors: Marek Stankevič, Michal K PietrusiewiczAbstract:Phosphinic acid chlorides are converted directly into phosphinous acid-Boranes in a process utilizing BH 3 .THF complex as a reducing agent. The process is general and affords phosphinous acid-Boranes in good to very high yields. Phosphinous acid-Boranes have been found to react readily with alkylating, acylating, reducing, halogenating and deborating agents to produce the corresponding phosphinous acid-Borane esters, phosphinous acid-Borane anhydrides, sec-phosphine oxides, sec-phosphine Boranes and phosphinic acid halides, respectively. The efficient procedures for these conversions have been developed and their scope has been outlined.
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direct conversion of sec phosphine oxides into phosphinous acid Boranes
Synlett, 2004Co-Authors: Marek Stankevič, Grzegorz Andrijewski, Michal K PietrusiewiczAbstract:Two straightforward and general procedures for the synthesis of phosphinous acid-Boranes directly from sec-phosphine oxides and Borane reagents under basic and under neutral conditions have been developed. The conversion is stereoselective and occurs with predominant inversion of configuration at P. The protonation constants of a representative series of phosphinous acid-phosphinous acid-Boranes have been determined.
Momar Toure - One of the best experts on this subject based on the ideXlab platform.
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Asymmetric Rhodium-Directed anti-Markovnikov Regioselective Boracyclopentannulation
Journal of the American Chemical Society, 2012Co-Authors: Momar Toure, Olivier Chuzel, Jean-luc ParrainAbstract:A Shimoi-type activation of B−H bond of NHC-Boranes by a diphosphane-ligated cationic Rh complex was applied in an unprecedented intramolecular hydroboration reaction of simple olefins. The use of NHCBoranes as hydroborating reagents is still undisclosed due to their nonreactivity toward alkenes which could be explained by the high stability of this complex rendering it unable to provide a "free" Borane hydroborating reagent. B−H bond Rh activation of NHC-Borane circumvents this limitation, and asymmetric Rh-directed anti-Markovnikov boracyclopentannulation reaction led to a library of enantioenriched cyclic Boranes in high yield (up to 94%) with high regio- (up to 100%) and enantioselectivity (er up to 99.2:0.8). This new activation mode of NHCBoranesn highlights their use in organometallic chemistry and offers a very good approach to access chiral cyclic NHC-Boranes.
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Asymmetric Rhodium-Directed anti-Markovnikov Regioselective Boracyclopentannulation
2012Co-Authors: Momar Toure, Olivier Chuzel, Jean-luc ParrainAbstract:A Shimoi-type activation of B–H bond of NHC-Boranes by a diphosphane-ligated cationic Rh complex was applied in an unprecedented intramolecular hydroboration reaction of simple olefins. The use of NHC-Boranes as hydroborating reagents is still undisclosed due to their nonreactivity toward alkenes which could be explained by the high stability of this complex rendering it unable to provide a “free” Borane hydroborating reagent. B–H bond Rh activation of NHC-Borane circumvents this limitation, and asymmetric Rh-directed anti-Markovnikov boracyclopentannulation reaction led to a library of enantioenriched cyclic Boranes in high yield (up to 94%) with high regio- (up to 100%) and enantioselectivity (er up to 99.2:0.8). This new activation mode of NHC-Boranes highlights their use in organometallic chemistry and offers a very good approach to access chiral cyclic NHC-Boranes
Marek Stankevič - One of the best experts on this subject based on the ideXlab platform.
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Resolution and stereochemistry of tert-butylphenylphosphinous acid-Borane.
Journal of Organic Chemistry, 2007Co-Authors: Marek Stankevič, K. Michał PietrusiewiczAbstract:A combined use of ephedrine and cinchonine as resolving agents enabled facile resolution of racemic tert-butylphenylphosphinous acid−Borane (1) into the two enantiomers in ca. 31−32% yield each. The resolved 1 served as a model substrate to study stereoselective synthetic transformations of phosphinous acid−Boranes yielding optically active phosphinite−Borane, boranatophosphinous−sulfonic anhydride, secondary phosphine−Borane, tertiary phosphine−Borane, secondary phosphine oxide, and phosphinic halides. By the judicious choice of the reaction paths, either enantiomer of tert-butylphenylphosphine−Borane and of tert-butylmethylphenylphosphine−Borane could be stereoselectively obtained from a single enantiomer of 1.
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the synthesis and reactivity of phosphinous acid Boranes
Synthesis, 2005Co-Authors: Marek Stankevič, Michal K PietrusiewiczAbstract:Phosphinic acid chlorides are converted directly into phosphinous acid-Boranes in a process utilizing BH 3 .THF complex as a reducing agent. The process is general and affords phosphinous acid-Boranes in good to very high yields. Phosphinous acid-Boranes have been found to react readily with alkylating, acylating, reducing, halogenating and deborating agents to produce the corresponding phosphinous acid-Borane esters, phosphinous acid-Borane anhydrides, sec-phosphine oxides, sec-phosphine Boranes and phosphinic acid halides, respectively. The efficient procedures for these conversions have been developed and their scope has been outlined.
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direct conversion of sec phosphine oxides into phosphinous acid Boranes
Synlett, 2004Co-Authors: Marek Stankevič, Grzegorz Andrijewski, Michal K PietrusiewiczAbstract:Two straightforward and general procedures for the synthesis of phosphinous acid-Boranes directly from sec-phosphine oxides and Borane reagents under basic and under neutral conditions have been developed. The conversion is stereoselective and occurs with predominant inversion of configuration at P. The protonation constants of a representative series of phosphinous acid-phosphinous acid-Boranes have been determined.
Max Malacria - One of the best experts on this subject based on the ideXlab platform.
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Preparation of NHC Borane Complexes by Lewis Base Exchange with Amine− and Phosphine−Boranes
The Journal of organic chemistry, 2010Co-Authors: Malika Makhlouf Brahmi, Emmanuel Lacôte, Dennis P Curran, Julien Monot, Marine Desage‐el Murr, Louis Fensterbank, Max MalacriaAbstract:A versatile new method for the preparation of NHC Boranes starting from two stable, readily available reactants-an heterocyclic salt and an amine or phosphine-Borane-is reported. It uses a Lewis base exchange at boron and provides easy access to new NHC Boranes, in particular B-substituted Borane ones.
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preparation of nhc Borane complexes by lewis base exchange with amine and phosphine Boranes
Journal of Organic Chemistry, 2010Co-Authors: Malika Makhlouf Brahmi, Emmanuel Lacôte, Dennis P Curran, Julien Monot, Louis Fensterbank, Marine Desageel Murr, Max MalacriaAbstract:A versatile new method for the preparation of NHC Boranes starting from two stable, readily available reactants-an heterocyclic salt and an amine or phosphine-Borane-is reported. It uses a Lewis base exchange at boron and provides easy access to new NHC Boranes, in particular B-substituted Borane ones.