The Experts below are selected from a list of 93 Experts worldwide ranked by ideXlab platform
Renato Noto - One of the best experts on this subject based on the ideXlab platform.
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polystyrene supported organocatalysts for α Selenenylation and michael reactions a common post modification approach for catalytic differentiation
Catalysis Communications, 2011Co-Authors: Francesco Giacalone, Michelangelo Gruttadauria, Paola Agrigento, Vincenzo Campisciano, Renato NotoAbstract:Abstract Three different resin-supported catalysts have been prepared by using the well established post-modification approach by means of thiol-ene coupling reaction. Two catalysts were tested for the first time in the asymmetric α-Selenenylation of propanal, while the third catalyst was used in the Michael addition reaction. While the preliminary results are not encouraging in the case of supported Jorgensen’ catalyst, interesting data have been collected with both for the supported MacMillan and prolyl-prolinol catalysts. In fact, these catalysts displayed good activity and selectivity. A reversed enantioselectivity in the α-Selenenylation was observed by changing the polarity of the solvent. Finally, these materials were easily recovered, and used four and five times, respectively.
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polystyrene supported proline and prolinamide versatile heterogeneous organocatalysts both for asymmetric aldol reaction in water and α Selenenylation of aldehydes
Tetrahedron Letters, 2007Co-Authors: Francesco Giacalone, Michelangelo Gruttadauria, Adriana Mossuto Marculescu, Renato NotoAbstract:A simple and efficient synthesis of polystyrene-supported proline and prolinamide has been carried out. Polystyrene-supported proline has been used as organocatalyst in the asymmetric aldol reaction between cyclohexanone and substituted benzaldehydes in water without any additive. High yields, diastereoselectivities and ee values have been observed. The versatility of this resin was demonstrated in the α-Selenenylation of aldehydes. Both proline and prolinamide resins gave high yields. Recycling studies showed that the proline resin gave better results than prolinamide resin.
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diastereoselective synthesis of 2 phenylselenenyl 1 3 anti diols and 2 phenylselenenyl 1 3 anti azido alcohols via hydroxy and azido Selenenylation reactions
Molecules, 2005Co-Authors: Serena Riela, Carmela Aprile, Michelangelo Gruttadauria, Paolo Lo Meo, Renato NotoAbstract:A method to synthesize 2-phenylselenenyl-1,3-anti-diols and 2-phenyl- selenenyl-1,3-anti-azidoalcohols via hydroxy- or azido-Selenenylation of trans-allylic alcohols is reported. Moreover, the first example of hydroxyl-Selenenylation of an allylic azide is presented. Yields ranging from moderate to good and diastereomeric ratios up to 95:5 are achieved.
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studies on the stereoselective selenolactonization hydroxy and methoxy Selenenylation of α and β hydroxy acids and esters synthesis of δ and γ lactones
ChemInform, 2003Co-Authors: Carmela Aprile, Michelangelo Gruttadauria, Maria E Amato, Francesca Danna, Paolo Lo Meo, Serena Riela, Renato NotoAbstract:Abstract The diastereoselective synthesis of hydroxy substituted γ- and δ-lactones was accomplished following two approaches. A 5- or 6-endo cyclization promoted by electrophilic selenium reagents of α- or β-hydroxy acids and a 5- or 6-exo cyclization of hydroxy esters obtained through a diastereoselective hydroxy Selenenylation reaction of α- or β-hydroxy esters. Moreover, the diastereoselective methoxy Selenenylation of the above compounds was investigated showing a case in which the compound that was unreactive in the hydroxy Selenenylation conditions gave, in the methoxy Selenenylation conditions, the deprotected diol. The usefulness of the methoxy Selenenylation procedure was proven by the preparation of a symmetric compound unsymmetrically functionalized. Yields and selectivities were found to depend on substituents (Ph or alkyl groups at the carbon atom that undergoes the nucleophilic attack), mode of cyclization, kinetic or thermodynamic control conditions. In the latter case, silica gel played an important role.
Michelangelo Gruttadauria - One of the best experts on this subject based on the ideXlab platform.
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polystyrene supported organocatalysts for α Selenenylation and michael reactions a common post modification approach for catalytic differentiation
Catalysis Communications, 2011Co-Authors: Francesco Giacalone, Michelangelo Gruttadauria, Paola Agrigento, Vincenzo Campisciano, Renato NotoAbstract:Abstract Three different resin-supported catalysts have been prepared by using the well established post-modification approach by means of thiol-ene coupling reaction. Two catalysts were tested for the first time in the asymmetric α-Selenenylation of propanal, while the third catalyst was used in the Michael addition reaction. While the preliminary results are not encouraging in the case of supported Jorgensen’ catalyst, interesting data have been collected with both for the supported MacMillan and prolyl-prolinol catalysts. In fact, these catalysts displayed good activity and selectivity. A reversed enantioselectivity in the α-Selenenylation was observed by changing the polarity of the solvent. Finally, these materials were easily recovered, and used four and five times, respectively.
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polystyrene supported proline and prolinamide versatile heterogeneous organocatalysts both for asymmetric aldol reaction in water and α Selenenylation of aldehydes
Tetrahedron Letters, 2007Co-Authors: Francesco Giacalone, Michelangelo Gruttadauria, Adriana Mossuto Marculescu, Renato NotoAbstract:A simple and efficient synthesis of polystyrene-supported proline and prolinamide has been carried out. Polystyrene-supported proline has been used as organocatalyst in the asymmetric aldol reaction between cyclohexanone and substituted benzaldehydes in water without any additive. High yields, diastereoselectivities and ee values have been observed. The versatility of this resin was demonstrated in the α-Selenenylation of aldehydes. Both proline and prolinamide resins gave high yields. Recycling studies showed that the proline resin gave better results than prolinamide resin.
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diastereoselective synthesis of 2 phenylselenenyl 1 3 anti diols and 2 phenylselenenyl 1 3 anti azido alcohols via hydroxy and azido Selenenylation reactions
Molecules, 2005Co-Authors: Serena Riela, Carmela Aprile, Michelangelo Gruttadauria, Paolo Lo Meo, Renato NotoAbstract:A method to synthesize 2-phenylselenenyl-1,3-anti-diols and 2-phenyl- selenenyl-1,3-anti-azidoalcohols via hydroxy- or azido-Selenenylation of trans-allylic alcohols is reported. Moreover, the first example of hydroxyl-Selenenylation of an allylic azide is presented. Yields ranging from moderate to good and diastereomeric ratios up to 95:5 are achieved.
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studies on the stereoselective selenolactonization hydroxy and methoxy Selenenylation of α and β hydroxy acids and esters synthesis of δ and γ lactones
ChemInform, 2003Co-Authors: Carmela Aprile, Michelangelo Gruttadauria, Maria E Amato, Francesca Danna, Paolo Lo Meo, Serena Riela, Renato NotoAbstract:Abstract The diastereoselective synthesis of hydroxy substituted γ- and δ-lactones was accomplished following two approaches. A 5- or 6-endo cyclization promoted by electrophilic selenium reagents of α- or β-hydroxy acids and a 5- or 6-exo cyclization of hydroxy esters obtained through a diastereoselective hydroxy Selenenylation reaction of α- or β-hydroxy esters. Moreover, the diastereoselective methoxy Selenenylation of the above compounds was investigated showing a case in which the compound that was unreactive in the hydroxy Selenenylation conditions gave, in the methoxy Selenenylation conditions, the deprotected diol. The usefulness of the methoxy Selenenylation procedure was proven by the preparation of a symmetric compound unsymmetrically functionalized. Yields and selectivities were found to depend on substituents (Ph or alkyl groups at the carbon atom that undergoes the nucleophilic attack), mode of cyclization, kinetic or thermodynamic control conditions. In the latter case, silica gel played an important role.
Serena Riela - One of the best experts on this subject based on the ideXlab platform.
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diastereoselective synthesis of 2 phenylselenenyl 1 3 anti diols and 2 phenylselenenyl 1 3 anti azido alcohols via hydroxy and azido Selenenylation reactions
Molecules, 2005Co-Authors: Serena Riela, Carmela Aprile, Michelangelo Gruttadauria, Paolo Lo Meo, Renato NotoAbstract:A method to synthesize 2-phenylselenenyl-1,3-anti-diols and 2-phenyl- selenenyl-1,3-anti-azidoalcohols via hydroxy- or azido-Selenenylation of trans-allylic alcohols is reported. Moreover, the first example of hydroxyl-Selenenylation of an allylic azide is presented. Yields ranging from moderate to good and diastereomeric ratios up to 95:5 are achieved.
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studies on the stereoselective selenolactonization hydroxy and methoxy Selenenylation of α and β hydroxy acids and esters synthesis of δ and γ lactones
ChemInform, 2003Co-Authors: Carmela Aprile, Michelangelo Gruttadauria, Maria E Amato, Francesca Danna, Paolo Lo Meo, Serena Riela, Renato NotoAbstract:Abstract The diastereoselective synthesis of hydroxy substituted γ- and δ-lactones was accomplished following two approaches. A 5- or 6-endo cyclization promoted by electrophilic selenium reagents of α- or β-hydroxy acids and a 5- or 6-exo cyclization of hydroxy esters obtained through a diastereoselective hydroxy Selenenylation reaction of α- or β-hydroxy esters. Moreover, the diastereoselective methoxy Selenenylation of the above compounds was investigated showing a case in which the compound that was unreactive in the hydroxy Selenenylation conditions gave, in the methoxy Selenenylation conditions, the deprotected diol. The usefulness of the methoxy Selenenylation procedure was proven by the preparation of a symmetric compound unsymmetrically functionalized. Yields and selectivities were found to depend on substituents (Ph or alkyl groups at the carbon atom that undergoes the nucleophilic attack), mode of cyclization, kinetic or thermodynamic control conditions. In the latter case, silica gel played an important role.
Jialiang Zhu - One of the best experts on this subject based on the ideXlab platform.
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efficient preparation of α α dialkyl α phenylselanyl acetates and α β unsaturated esters from the corresponding α α dialkyl α cyanoacetates by a lithium naphthalenide induced reductive Selenenylation process
Synthesis, 2007Co-Authors: Jialiang ZhuAbstract:An array of α,α-dialkyl-α-(phenylselanyl)acetates has been synthesized very efficiently from readily available a,a-dialkyl-a-cyanoacetates, by use of lithium naphthalenide induced reductive α-Selenenylation as a key operation. Moreover, the selanyl esters thus generated in situ could be converted further, in a one-pot treatment with hydrogen peroxide and acetic acid, into the corresponding α,β-unsaturated esters in moderate to high yields. The C=C bond formation was highly regio- and/or diastereoselective in some cases.
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lithium naphthalenide induced reductive Selenenylation of α cyano ketones a regiocontrolled process for α phenylseleno ketones and one pot conversion into enone system
Synlett, 2007Co-Authors: Jialiang Zhu, Chunwei Kuo, Kakshan ShiaAbstract:An efficient procedure for the regiocontrolled synthesis of α-phenylseleno ketones has been developed, making use of the lithium naphthalenide induced reductive Selenenylation of the α-cyano ketone system as a key operation. Moreover, seleno ketones thus generated in situ, upon subsequent treatment with hydrogen peroxide and acetic acid, could be further converted into the corresponding enones with a high degree of regioselectivity, presumably due to the lithium salt mediated selenoxide syn-elimination process.
Paolo Lo Meo - One of the best experts on this subject based on the ideXlab platform.
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diastereoselective synthesis of 2 phenylselenenyl 1 3 anti diols and 2 phenylselenenyl 1 3 anti azido alcohols via hydroxy and azido Selenenylation reactions
Molecules, 2005Co-Authors: Serena Riela, Carmela Aprile, Michelangelo Gruttadauria, Paolo Lo Meo, Renato NotoAbstract:A method to synthesize 2-phenylselenenyl-1,3-anti-diols and 2-phenyl- selenenyl-1,3-anti-azidoalcohols via hydroxy- or azido-Selenenylation of trans-allylic alcohols is reported. Moreover, the first example of hydroxyl-Selenenylation of an allylic azide is presented. Yields ranging from moderate to good and diastereomeric ratios up to 95:5 are achieved.
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studies on the stereoselective selenolactonization hydroxy and methoxy Selenenylation of α and β hydroxy acids and esters synthesis of δ and γ lactones
ChemInform, 2003Co-Authors: Carmela Aprile, Michelangelo Gruttadauria, Maria E Amato, Francesca Danna, Paolo Lo Meo, Serena Riela, Renato NotoAbstract:Abstract The diastereoselective synthesis of hydroxy substituted γ- and δ-lactones was accomplished following two approaches. A 5- or 6-endo cyclization promoted by electrophilic selenium reagents of α- or β-hydroxy acids and a 5- or 6-exo cyclization of hydroxy esters obtained through a diastereoselective hydroxy Selenenylation reaction of α- or β-hydroxy esters. Moreover, the diastereoselective methoxy Selenenylation of the above compounds was investigated showing a case in which the compound that was unreactive in the hydroxy Selenenylation conditions gave, in the methoxy Selenenylation conditions, the deprotected diol. The usefulness of the methoxy Selenenylation procedure was proven by the preparation of a symmetric compound unsymmetrically functionalized. Yields and selectivities were found to depend on substituents (Ph or alkyl groups at the carbon atom that undergoes the nucleophilic attack), mode of cyclization, kinetic or thermodynamic control conditions. In the latter case, silica gel played an important role.