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Carmen Najera - One of the best experts on this subject based on the ideXlab platform.
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3 5 bis trifluoromethyl phenyl Sulfones for the highly stereoselective julia kocienski synthesis of α β unsaturated esters and weinreb amides
European Journal of Organic Chemistry, 2008Co-Authors: Diego A. Alonso, Mónica Fuensanta, Enrique Gomezbengoa, Carmen NajeraAbstract:The 3,5-bis(trifluoromethyl)phenyl (BTFP) Sulfones tert-butyl α-(BTFPsulfonyl)acetate (4) and Weinreb α-(BTFPsulfonyl)acetamide (5) have successfully been employed in the Julia–Kocienski olefination of aldehydes with K2CO3 as the base at 120 °C in DMF under solid/liquid phase-transfer catalysis conditions to afford α,β-unsaturated esters and Weinreb amides, respectively. The corresponding products were obtained in good yields and with high E stereoselectivities (E/Z up to >99:1), especially in the case of the amides. A detailed computational study of the Julia–Kocienski olefination with BTFP Sulfone 4 was carried out and confirmed the existence of an equilibrium in the initial addition of the Sulfone enolate to the aldehyde and, in contrast to other proposed mechanisms, a non-concerted final elimination of SO2 and 3,5-bis(trifluoromethyl)phenoxide. A plausible explanation for the high E diastereoselectivity observed in the reaction has been suggested based on kinetic considerations at spirocyclic TS2 and thermodynamic factors during the elimination after TS2. ESI-MS studies carried out during the olefination reaction of benzaldehyde with BTFP Sulfone 4 were used to characterize the Sulfone enolate and the intermediate assumed for the reaction mechanism. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
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3,5‐Bis(trifluoromethyl)phenyl Sulfones for the Highly Stereoselective Julia–Kocienski Synthesis of α,β‐Unsaturated Esters and Weinreb Amides
European Journal of Organic Chemistry, 2008Co-Authors: Diego A. Alonso, Mónica Fuensanta, Enrique Gómez-bengoa, Carmen NajeraAbstract:The 3,5-bis(trifluoromethyl)phenyl (BTFP) Sulfones tert-butyl α-(BTFPsulfonyl)acetate (4) and Weinreb α-(BTFPsulfonyl)acetamide (5) have successfully been employed in the Julia–Kocienski olefination of aldehydes with K2CO3 as the base at 120 °C in DMF under solid/liquid phase-transfer catalysis conditions to afford α,β-unsaturated esters and Weinreb amides, respectively. The corresponding products were obtained in good yields and with high E stereoselectivities (E/Z up to >99:1), especially in the case of the amides. A detailed computational study of the Julia–Kocienski olefination with BTFP Sulfone 4 was carried out and confirmed the existence of an equilibrium in the initial addition of the Sulfone enolate to the aldehyde and, in contrast to other proposed mechanisms, a non-concerted final elimination of SO2 and 3,5-bis(trifluoromethyl)phenoxide. A plausible explanation for the high E diastereoselectivity observed in the reaction has been suggested based on kinetic considerations at spirocyclic TS2 and thermodynamic factors during the elimination after TS2. ESI-MS studies carried out during the olefination reaction of benzaldehyde with BTFP Sulfone 4 were used to characterize the Sulfone enolate and the intermediate assumed for the reaction mechanism. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
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3,5‐Bis(trifluoromethyl)phenyl Sulfones in the Julia–Kocienski Olefination – Application to the Synthesis of Tri‐ and Tetrasubstituted Olefins
European Journal of Organic Chemistry, 2006Co-Authors: Diego A. Alonso, Mónica Fuensanta, Carmen NajeraAbstract:3,5-Bis(trifluoromethyl)phenyl (BTFP) Sulfones 8a–d are successfully employed in the modified Julia olefination reaction with carbonyl compounds employing phosphazene base P4-tBu at room temp. in THF, affording tri- and tetrasubstituted olefins in good yields. The Julia–Kocienski olefination between primary alkyl BTFP Sulfones 8a,b and aromatic and aliphatic ketones affords the corresponding trisubstituted alkenes in good yields and low stereoselectivities. On the other hand, higher yields and stereoselectivities are obtained in the synthesis of trisubstituted olefins through the other approach, the coupling of secondary alkyl BTFP Sulfones 8c,d with aliphatic, aromatic and α,β-unsaturated aldehydes. For the first time, tetrasubstituted olefins are synthesized by means of the Julia–Kocienski protocol when the isopropyl BTFP Sulfone 8c reacts with aliphatic and aromatic ketones, employing P4-tBu as base at THF reflux. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
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3 5 bis trifluoromethyl phenyl Sulfones in the julia kocienski olefination application to the synthesis of tri and tetrasubstituted olefins
European Journal of Organic Chemistry, 2006Co-Authors: Diego A. Alonso, Mónica Fuensanta, Carmen NajeraAbstract:3,5-Bis(trifluoromethyl)phenyl (BTFP) Sulfones 8a–d are successfully employed in the modified Julia olefination reaction with carbonyl compounds employing phosphazene base P4-tBu at room temp. in THF, affording tri- and tetrasubstituted olefins in good yields. The Julia–Kocienski olefination between primary alkyl BTFP Sulfones 8a,b and aromatic and aliphatic ketones affords the corresponding trisubstituted alkenes in good yields and low stereoselectivities. On the other hand, higher yields and stereoselectivities are obtained in the synthesis of trisubstituted olefins through the other approach, the coupling of secondary alkyl BTFP Sulfones 8c,d with aliphatic, aromatic and α,β-unsaturated aldehydes. For the first time, tetrasubstituted olefins are synthesized by means of the Julia–Kocienski protocol when the isopropyl BTFP Sulfone 8c reacts with aliphatic and aromatic ketones, employing P4-tBu as base at THF reflux. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Diego A. Alonso - One of the best experts on this subject based on the ideXlab platform.
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3 5 bis trifluoromethyl phenyl Sulfones for the highly stereoselective julia kocienski synthesis of α β unsaturated esters and weinreb amides
European Journal of Organic Chemistry, 2008Co-Authors: Diego A. Alonso, Mónica Fuensanta, Enrique Gomezbengoa, Carmen NajeraAbstract:The 3,5-bis(trifluoromethyl)phenyl (BTFP) Sulfones tert-butyl α-(BTFPsulfonyl)acetate (4) and Weinreb α-(BTFPsulfonyl)acetamide (5) have successfully been employed in the Julia–Kocienski olefination of aldehydes with K2CO3 as the base at 120 °C in DMF under solid/liquid phase-transfer catalysis conditions to afford α,β-unsaturated esters and Weinreb amides, respectively. The corresponding products were obtained in good yields and with high E stereoselectivities (E/Z up to >99:1), especially in the case of the amides. A detailed computational study of the Julia–Kocienski olefination with BTFP Sulfone 4 was carried out and confirmed the existence of an equilibrium in the initial addition of the Sulfone enolate to the aldehyde and, in contrast to other proposed mechanisms, a non-concerted final elimination of SO2 and 3,5-bis(trifluoromethyl)phenoxide. A plausible explanation for the high E diastereoselectivity observed in the reaction has been suggested based on kinetic considerations at spirocyclic TS2 and thermodynamic factors during the elimination after TS2. ESI-MS studies carried out during the olefination reaction of benzaldehyde with BTFP Sulfone 4 were used to characterize the Sulfone enolate and the intermediate assumed for the reaction mechanism. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
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3,5‐Bis(trifluoromethyl)phenyl Sulfones for the Highly Stereoselective Julia–Kocienski Synthesis of α,β‐Unsaturated Esters and Weinreb Amides
European Journal of Organic Chemistry, 2008Co-Authors: Diego A. Alonso, Mónica Fuensanta, Enrique Gómez-bengoa, Carmen NajeraAbstract:The 3,5-bis(trifluoromethyl)phenyl (BTFP) Sulfones tert-butyl α-(BTFPsulfonyl)acetate (4) and Weinreb α-(BTFPsulfonyl)acetamide (5) have successfully been employed in the Julia–Kocienski olefination of aldehydes with K2CO3 as the base at 120 °C in DMF under solid/liquid phase-transfer catalysis conditions to afford α,β-unsaturated esters and Weinreb amides, respectively. The corresponding products were obtained in good yields and with high E stereoselectivities (E/Z up to >99:1), especially in the case of the amides. A detailed computational study of the Julia–Kocienski olefination with BTFP Sulfone 4 was carried out and confirmed the existence of an equilibrium in the initial addition of the Sulfone enolate to the aldehyde and, in contrast to other proposed mechanisms, a non-concerted final elimination of SO2 and 3,5-bis(trifluoromethyl)phenoxide. A plausible explanation for the high E diastereoselectivity observed in the reaction has been suggested based on kinetic considerations at spirocyclic TS2 and thermodynamic factors during the elimination after TS2. ESI-MS studies carried out during the olefination reaction of benzaldehyde with BTFP Sulfone 4 were used to characterize the Sulfone enolate and the intermediate assumed for the reaction mechanism. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
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3,5‐Bis(trifluoromethyl)phenyl Sulfones in the Julia–Kocienski Olefination – Application to the Synthesis of Tri‐ and Tetrasubstituted Olefins
European Journal of Organic Chemistry, 2006Co-Authors: Diego A. Alonso, Mónica Fuensanta, Carmen NajeraAbstract:3,5-Bis(trifluoromethyl)phenyl (BTFP) Sulfones 8a–d are successfully employed in the modified Julia olefination reaction with carbonyl compounds employing phosphazene base P4-tBu at room temp. in THF, affording tri- and tetrasubstituted olefins in good yields. The Julia–Kocienski olefination between primary alkyl BTFP Sulfones 8a,b and aromatic and aliphatic ketones affords the corresponding trisubstituted alkenes in good yields and low stereoselectivities. On the other hand, higher yields and stereoselectivities are obtained in the synthesis of trisubstituted olefins through the other approach, the coupling of secondary alkyl BTFP Sulfones 8c,d with aliphatic, aromatic and α,β-unsaturated aldehydes. For the first time, tetrasubstituted olefins are synthesized by means of the Julia–Kocienski protocol when the isopropyl BTFP Sulfone 8c reacts with aliphatic and aromatic ketones, employing P4-tBu as base at THF reflux. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
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3 5 bis trifluoromethyl phenyl Sulfones in the julia kocienski olefination application to the synthesis of tri and tetrasubstituted olefins
European Journal of Organic Chemistry, 2006Co-Authors: Diego A. Alonso, Mónica Fuensanta, Carmen NajeraAbstract:3,5-Bis(trifluoromethyl)phenyl (BTFP) Sulfones 8a–d are successfully employed in the modified Julia olefination reaction with carbonyl compounds employing phosphazene base P4-tBu at room temp. in THF, affording tri- and tetrasubstituted olefins in good yields. The Julia–Kocienski olefination between primary alkyl BTFP Sulfones 8a,b and aromatic and aliphatic ketones affords the corresponding trisubstituted alkenes in good yields and low stereoselectivities. On the other hand, higher yields and stereoselectivities are obtained in the synthesis of trisubstituted olefins through the other approach, the coupling of secondary alkyl BTFP Sulfones 8c,d with aliphatic, aromatic and α,β-unsaturated aldehydes. For the first time, tetrasubstituted olefins are synthesized by means of the Julia–Kocienski protocol when the isopropyl BTFP Sulfone 8c reacts with aliphatic and aromatic ketones, employing P4-tBu as base at THF reflux. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Mónica Fuensanta - One of the best experts on this subject based on the ideXlab platform.
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3 5 bis trifluoromethyl phenyl Sulfones for the highly stereoselective julia kocienski synthesis of α β unsaturated esters and weinreb amides
European Journal of Organic Chemistry, 2008Co-Authors: Diego A. Alonso, Mónica Fuensanta, Enrique Gomezbengoa, Carmen NajeraAbstract:The 3,5-bis(trifluoromethyl)phenyl (BTFP) Sulfones tert-butyl α-(BTFPsulfonyl)acetate (4) and Weinreb α-(BTFPsulfonyl)acetamide (5) have successfully been employed in the Julia–Kocienski olefination of aldehydes with K2CO3 as the base at 120 °C in DMF under solid/liquid phase-transfer catalysis conditions to afford α,β-unsaturated esters and Weinreb amides, respectively. The corresponding products were obtained in good yields and with high E stereoselectivities (E/Z up to >99:1), especially in the case of the amides. A detailed computational study of the Julia–Kocienski olefination with BTFP Sulfone 4 was carried out and confirmed the existence of an equilibrium in the initial addition of the Sulfone enolate to the aldehyde and, in contrast to other proposed mechanisms, a non-concerted final elimination of SO2 and 3,5-bis(trifluoromethyl)phenoxide. A plausible explanation for the high E diastereoselectivity observed in the reaction has been suggested based on kinetic considerations at spirocyclic TS2 and thermodynamic factors during the elimination after TS2. ESI-MS studies carried out during the olefination reaction of benzaldehyde with BTFP Sulfone 4 were used to characterize the Sulfone enolate and the intermediate assumed for the reaction mechanism. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
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3,5‐Bis(trifluoromethyl)phenyl Sulfones for the Highly Stereoselective Julia–Kocienski Synthesis of α,β‐Unsaturated Esters and Weinreb Amides
European Journal of Organic Chemistry, 2008Co-Authors: Diego A. Alonso, Mónica Fuensanta, Enrique Gómez-bengoa, Carmen NajeraAbstract:The 3,5-bis(trifluoromethyl)phenyl (BTFP) Sulfones tert-butyl α-(BTFPsulfonyl)acetate (4) and Weinreb α-(BTFPsulfonyl)acetamide (5) have successfully been employed in the Julia–Kocienski olefination of aldehydes with K2CO3 as the base at 120 °C in DMF under solid/liquid phase-transfer catalysis conditions to afford α,β-unsaturated esters and Weinreb amides, respectively. The corresponding products were obtained in good yields and with high E stereoselectivities (E/Z up to >99:1), especially in the case of the amides. A detailed computational study of the Julia–Kocienski olefination with BTFP Sulfone 4 was carried out and confirmed the existence of an equilibrium in the initial addition of the Sulfone enolate to the aldehyde and, in contrast to other proposed mechanisms, a non-concerted final elimination of SO2 and 3,5-bis(trifluoromethyl)phenoxide. A plausible explanation for the high E diastereoselectivity observed in the reaction has been suggested based on kinetic considerations at spirocyclic TS2 and thermodynamic factors during the elimination after TS2. ESI-MS studies carried out during the olefination reaction of benzaldehyde with BTFP Sulfone 4 were used to characterize the Sulfone enolate and the intermediate assumed for the reaction mechanism. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
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3,5‐Bis(trifluoromethyl)phenyl Sulfones in the Julia–Kocienski Olefination – Application to the Synthesis of Tri‐ and Tetrasubstituted Olefins
European Journal of Organic Chemistry, 2006Co-Authors: Diego A. Alonso, Mónica Fuensanta, Carmen NajeraAbstract:3,5-Bis(trifluoromethyl)phenyl (BTFP) Sulfones 8a–d are successfully employed in the modified Julia olefination reaction with carbonyl compounds employing phosphazene base P4-tBu at room temp. in THF, affording tri- and tetrasubstituted olefins in good yields. The Julia–Kocienski olefination between primary alkyl BTFP Sulfones 8a,b and aromatic and aliphatic ketones affords the corresponding trisubstituted alkenes in good yields and low stereoselectivities. On the other hand, higher yields and stereoselectivities are obtained in the synthesis of trisubstituted olefins through the other approach, the coupling of secondary alkyl BTFP Sulfones 8c,d with aliphatic, aromatic and α,β-unsaturated aldehydes. For the first time, tetrasubstituted olefins are synthesized by means of the Julia–Kocienski protocol when the isopropyl BTFP Sulfone 8c reacts with aliphatic and aromatic ketones, employing P4-tBu as base at THF reflux. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
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3 5 bis trifluoromethyl phenyl Sulfones in the julia kocienski olefination application to the synthesis of tri and tetrasubstituted olefins
European Journal of Organic Chemistry, 2006Co-Authors: Diego A. Alonso, Mónica Fuensanta, Carmen NajeraAbstract:3,5-Bis(trifluoromethyl)phenyl (BTFP) Sulfones 8a–d are successfully employed in the modified Julia olefination reaction with carbonyl compounds employing phosphazene base P4-tBu at room temp. in THF, affording tri- and tetrasubstituted olefins in good yields. The Julia–Kocienski olefination between primary alkyl BTFP Sulfones 8a,b and aromatic and aliphatic ketones affords the corresponding trisubstituted alkenes in good yields and low stereoselectivities. On the other hand, higher yields and stereoselectivities are obtained in the synthesis of trisubstituted olefins through the other approach, the coupling of secondary alkyl BTFP Sulfones 8c,d with aliphatic, aromatic and α,β-unsaturated aldehydes. For the first time, tetrasubstituted olefins are synthesized by means of the Julia–Kocienski protocol when the isopropyl BTFP Sulfone 8c reacts with aliphatic and aromatic ketones, employing P4-tBu as base at THF reflux. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Austen C Angell - One of the best experts on this subject based on the ideXlab platform.
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Sulfone based electrolytes for lithium ion batteries
Journal of The Electrochemical Society, 2002Co-Authors: Austen C AngellAbstract:A series of cyclic or acyclic Sulfones have been synthesized and evaluated as electrolyte solvents for lithium (ion) batteries. This report summarizes the physical and electrochemical properties of these new compounds. It is found that, while the anodic stability of these solvents is independent of the Sulfone structure, i.e., no oxidative decomposition is observed before 5.5 V vs. Li in any Sulfone, the structure of their alkyl substituents dictates their compatibility with graphitic anodes. In the most favorable cases, this compatibility is comparable with that found with carbonate-based electrolytes. Fluorination of alkyl groups in the Sulfone seems to help in forming a stable solid electrolyte interface on the anode, while also improving the conductivity. Initial tests of these cells containing such electrolyte solvents show promising performance.
Enrique Gomezbengoa - One of the best experts on this subject based on the ideXlab platform.
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3 5 bis trifluoromethyl phenyl Sulfones for the highly stereoselective julia kocienski synthesis of α β unsaturated esters and weinreb amides
European Journal of Organic Chemistry, 2008Co-Authors: Diego A. Alonso, Mónica Fuensanta, Enrique Gomezbengoa, Carmen NajeraAbstract:The 3,5-bis(trifluoromethyl)phenyl (BTFP) Sulfones tert-butyl α-(BTFPsulfonyl)acetate (4) and Weinreb α-(BTFPsulfonyl)acetamide (5) have successfully been employed in the Julia–Kocienski olefination of aldehydes with K2CO3 as the base at 120 °C in DMF under solid/liquid phase-transfer catalysis conditions to afford α,β-unsaturated esters and Weinreb amides, respectively. The corresponding products were obtained in good yields and with high E stereoselectivities (E/Z up to >99:1), especially in the case of the amides. A detailed computational study of the Julia–Kocienski olefination with BTFP Sulfone 4 was carried out and confirmed the existence of an equilibrium in the initial addition of the Sulfone enolate to the aldehyde and, in contrast to other proposed mechanisms, a non-concerted final elimination of SO2 and 3,5-bis(trifluoromethyl)phenoxide. A plausible explanation for the high E diastereoselectivity observed in the reaction has been suggested based on kinetic considerations at spirocyclic TS2 and thermodynamic factors during the elimination after TS2. ESI-MS studies carried out during the olefination reaction of benzaldehyde with BTFP Sulfone 4 were used to characterize the Sulfone enolate and the intermediate assumed for the reaction mechanism. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
