The Experts below are selected from a list of 78 Experts worldwide ranked by ideXlab platform
Declan G Gilheany - One of the best experts on this subject based on the ideXlab platform.
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systematic survey of positive chlorine sources in the asymmetric Appel Reaction oxalyl chloride as a new phosphine activator
Tetrahedron Letters, 2013Co-Authors: Kamalraj V Rajendran, Lorna Kennedy, Cormac T Oconnor, Enda Bergin, Declan G GilheanyAbstract:Abstract A wide selection of phosphine activators has been screened to improve the selection process in the asymmetric Appel Reaction. Of the activators screened, hexachloroacetone (HCA) gave the highest selectivity with excellent yield, but at least one of its by-products, pentachloroacetone (PCA), can become involved in the selection process. In addressing this, a new Reaction of phosphines with oxalyl chloride was discovered that can also generate the key intermediate chlorophosphonium salt (CPS), gives better enantioselectivity and possesses significant advantages over other phosphine activators.
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synthesis of 2 3 dihydro 1 phenylbenzo b phosphole 1 phenylphosphindane and its use as a mechanistic test in the asymmetric Appel Reaction decisive evidence against involvement of pseudorotation in the stereoselecting step
Journal of Organic Chemistry, 2013Co-Authors: Damien J Carr, Jaya Satyanarayana Kudavalli, Katherine S Dunne, Helge Mullerbunz, Declan G GilheanyAbstract:Racemic 2,3-dihydro-1-phenylbenzo[b]phosphole was obtained by reduction of 1-phenylbenzo[b]phosphole-1-oxide, itself derived by ring-closing metathesis of phenylstyrylvinylphosphine oxide. The title compound was then reoxidized under asymmetric Appel conditions. Comparison of the sense and degree of the stereoselectivity to those obtained with an open-chain analogue indicated that the ring system does not affect the selectivity of the process. This in turn strongly suggests that the stereoselection is not related to pseudorotamer preferences in putative phosphorane intermediates.
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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.
Kamalraj V Rajendran - One of the best experts on this subject based on the ideXlab platform.
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systematic survey of positive chlorine sources in the asymmetric Appel Reaction oxalyl chloride as a new phosphine activator
Tetrahedron Letters, 2013Co-Authors: Kamalraj V Rajendran, Lorna Kennedy, Cormac T Oconnor, Enda Bergin, Declan G GilheanyAbstract:Abstract A wide selection of phosphine activators has been screened to improve the selection process in the asymmetric Appel Reaction. Of the activators screened, hexachloroacetone (HCA) gave the highest selectivity with excellent yield, but at least one of its by-products, pentachloroacetone (PCA), can become involved in the selection process. In addressing this, a new Reaction of phosphines with oxalyl chloride was discovered that can also generate the key intermediate chlorophosphonium salt (CPS), gives better enantioselectivity and possesses significant advantages over other phosphine activators.
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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.
Katherine S Dunne - One of the best experts on this subject based on the ideXlab platform.
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synthesis of 2 3 dihydro 1 phenylbenzo b phosphole 1 phenylphosphindane and its use as a mechanistic test in the asymmetric Appel Reaction decisive evidence against involvement of pseudorotation in the stereoselecting step
Journal of Organic Chemistry, 2013Co-Authors: Damien J Carr, Jaya Satyanarayana Kudavalli, Katherine S Dunne, Helge Mullerbunz, Declan G GilheanyAbstract:Racemic 2,3-dihydro-1-phenylbenzo[b]phosphole was obtained by reduction of 1-phenylbenzo[b]phosphole-1-oxide, itself derived by ring-closing metathesis of phenylstyrylvinylphosphine oxide. The title compound was then reoxidized under asymmetric Appel conditions. Comparison of the sense and degree of the stereoselectivity to those obtained with an open-chain analogue indicated that the ring system does not affect the selectivity of the process. This in turn strongly suggests that the stereoselection is not related to pseudorotamer preferences in putative phosphorane intermediates.
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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.
Jaya Satyanarayana Kudavalli - One of the best experts on this subject based on the ideXlab platform.
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synthesis of 2 3 dihydro 1 phenylbenzo b phosphole 1 phenylphosphindane and its use as a mechanistic test in the asymmetric Appel Reaction decisive evidence against involvement of pseudorotation in the stereoselecting step
Journal of Organic Chemistry, 2013Co-Authors: Damien J Carr, Jaya Satyanarayana Kudavalli, Katherine S Dunne, Helge Mullerbunz, Declan G GilheanyAbstract:Racemic 2,3-dihydro-1-phenylbenzo[b]phosphole was obtained by reduction of 1-phenylbenzo[b]phosphole-1-oxide, itself derived by ring-closing metathesis of phenylstyrylvinylphosphine oxide. The title compound was then reoxidized under asymmetric Appel conditions. Comparison of the sense and degree of the stereoselectivity to those obtained with an open-chain analogue indicated that the ring system does not affect the selectivity of the process. This in turn strongly suggests that the stereoselection is not related to pseudorotamer preferences in putative phosphorane intermediates.
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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.
Marc C Kimber - One of the best experts on this subject based on the ideXlab platform.
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a biosynthetically inspired route to substituted furans using the Appel Reaction total synthesis of the furan fatty acid f5
Chemical Communications, 2017Co-Authors: Martin R Lindley, Gareth J Pritchard, Marc C KimberAbstract:Appel Reaction conditions have been harnessed to affect a mild biosynthetically inspired dehydration of endoperoxides to deliver multi-substituted electron rich furans. Unlike traditional dehydrative procedures, this method is metal and acid free, and can be achieved under redox neutral conditions. It is general for a range of aryl and alkyl substituted endoperoxides, and is functional group tolerant. Furthermore, this procedure has been used to deliver an effective total synthesis of the furan fatty acid (FFA) F5.