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Tamotsu Takahashi - One of the best experts on this subject based on the ideXlab platform.
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Preparation of partially substituted 1-halo- and 1,4-dihalo-1,3-dienes via reagent-controlled Desilylation of halogenated 1,3-dienes.
The Journal of organic chemistry, 2006Co-Authors: Zhiyi Song, Guangzhen Liu, Xiaozhong Liu, Tamotsu TakahashiAbstract:Depending on the Desilylation reagents used, 1-halo-1,4-bis(trimethylsilyl)-1,3-butadienes afforded either 1-halo-1-trimethylsilyl-1,3-butadienes or 1-halo-4-trimethylsilyl-1,3-butadienes in excellent yields with excellent selectivity, respectively, when treated with CF3COOH or with NaOMe. These monosilylated 1,3-butadiene products could be further desilylated to generate their corresponding halobutadienes via the above reagent-controlled Desilylation reaction. When 1,4-dihalo-1,4-bis(trimethylsilyl)-1,3-dienes were treated with MeONa/MeOH at room temperature, Desilylation of both of the two trimethylsilyl groups took place to afford their corresponding 1,4-dihalo-1,3-dienes in excellent yields. The commonly used Desilylation reagent CF3COOH did not work for these dihalobutadienes.
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Synthesis of 1,1,4,4-Tetrabromo-2-butenes and Related Compounds via Desilylation−Bromination of Silylated 1,3-Butadiene Derivatives
The Journal of organic chemistry, 2004Co-Authors: Xiaozhong Liu, Fengyu Bao, Hongtao Fan, Tamotsu TakahashiAbstract:The combination of zirconocene-mediated coupling of silylated alkynes with a protonation-Desilylation or bromination-Desilylation process afforded otherwise unavailable butadiene derivatives. When (E,E)-2,3-dialkyl-1,4-bis(trimethylsilyl)-1,3-butadienes were treated with 3 equiv of Br(2) in CH(2)Cl(2), (E)-2,3-dialkyl-1,1,4,4-tetrabromo-2-butenes were obtained in excellent yields with perfect stereoselectivity.
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synthesis of 1 1 4 4 tetrabromo 2 butenes and related compounds via Desilylation bromination of silylated 1 3 butadiene derivatives
Journal of Organic Chemistry, 2004Co-Authors: Xiaozhong Liu, Fengyu Bao, Hongtao Fan, Tamotsu TakahashiAbstract:The combination of zirconocene-mediated coupling of silylated alkynes with a protonation-Desilylation or bromination-Desilylation process afforded otherwise unavailable butadiene derivatives. When (E,E)-2,3-dialkyl-1,4-bis(trimethylsilyl)-1,3-butadienes were treated with 3 equiv of Br(2) in CH(2)Cl(2), (E)-2,3-dialkyl-1,1,4,4-tetrabromo-2-butenes were obtained in excellent yields with perfect stereoselectivity.
Piero Salvadori - One of the best experts on this subject based on the ideXlab platform.
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silylation Desilylation of propargyl amides rapid synthesis of functionalised aldehydes and β lactams
Tetrahedron, 2007Co-Authors: Laura Antonella Aronica, Giulia Valentini, Anna Maria Caporusso, Piero SalvadoriAbstract:Abstract Propargyl functionalised β-silylalkenals were easily prepared starting from suitable propargyl compounds by a silylformylation process. In particular the use of propargyl tosyl amides allowed the synthesis of α,β-unsaturated aldehydes through a two-step sequence of silylformylation–Desilylation reactions. TBAF was employed to induce the Desilylation process that was performed under very mild experimental conditions and occurred along with an elimination step of the tosylamido moiety affording 2-methylaryl-2-alkenals with good yields and stereoselectivity. When the tosyl amides were reacted with a hydrosilane in the presence of catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) α-silylmethylene-β-lactams were synthesised through a silylcarbocyclisation process. A high chemoselectivity towards the β-lactam was observed when dialkyl propargyl amides were employed. The obtained β-lactams were easily transformed into the corresponding methylaryl-β-lactams by fluoride induced aryl migration–Desilylation with total retention of configuration of the migrating group and complete stereoselectivity towards the more stable β-lactam ( E )-isomer.
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Silylation–Desilylation of propargyl amides: rapid synthesis of functionalised aldehydes and β-lactams
Tetrahedron, 2007Co-Authors: Laura Antonella Aronica, Giulia Valentini, Anna Maria Caporusso, Piero SalvadoriAbstract:Abstract Propargyl functionalised β-silylalkenals were easily prepared starting from suitable propargyl compounds by a silylformylation process. In particular the use of propargyl tosyl amides allowed the synthesis of α,β-unsaturated aldehydes through a two-step sequence of silylformylation–Desilylation reactions. TBAF was employed to induce the Desilylation process that was performed under very mild experimental conditions and occurred along with an elimination step of the tosylamido moiety affording 2-methylaryl-2-alkenals with good yields and stereoselectivity. When the tosyl amides were reacted with a hydrosilane in the presence of catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) α-silylmethylene-β-lactams were synthesised through a silylcarbocyclisation process. A high chemoselectivity towards the β-lactam was observed when dialkyl propargyl amides were employed. The obtained β-lactams were easily transformed into the corresponding methylaryl-β-lactams by fluoride induced aryl migration–Desilylation with total retention of configuration of the migrating group and complete stereoselectivity towards the more stable β-lactam ( E )-isomer.
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silylformylation Desilylation of propargyl amides synthesis of α β unsaturated aldehydes
Tetrahedron Letters, 2006Co-Authors: Laura Antonella Aronica, Giulia Valentini, Anna Maria Caporusso, Patrizio Raffa, Piero SalvadoriAbstract:Abstract α,β-Unsaturated aldehydes are prepared from easily available propargyl amides through a two-step sequence of silylformylation–Desilylation reactions. The substituent on the nitrogen atom markedly influences both reactions, β-silylalkenals being formed in the presence of tosyl or tert -butoxycarbonyl protected amines. TBAF is employed to induce the Desilylation process that is performed under very mild experimental conditions. A contemporary elimination step occurs when tosylamido aldehydes are reacted affording 2-methylaryl-2-alkenals, while this process can be suppressed changing the functional group to NBOC, thus allowing the formation of β-amino carbonyl compounds.
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Silylformylation–Desilylation of propargyl amides: synthesis of α,β-unsaturated aldehydes
Tetrahedron Letters, 2006Co-Authors: Laura Antonella Aronica, Giulia Valentini, Anna Maria Caporusso, Patrizio Raffa, Piero SalvadoriAbstract:Abstract α,β-Unsaturated aldehydes are prepared from easily available propargyl amides through a two-step sequence of silylformylation–Desilylation reactions. The substituent on the nitrogen atom markedly influences both reactions, β-silylalkenals being formed in the presence of tosyl or tert -butoxycarbonyl protected amines. TBAF is employed to induce the Desilylation process that is performed under very mild experimental conditions. A contemporary elimination step occurs when tosylamido aldehydes are reacted affording 2-methylaryl-2-alkenals, while this process can be suppressed changing the functional group to NBOC, thus allowing the formation of β-amino carbonyl compounds.
Xiaozhong Liu - One of the best experts on this subject based on the ideXlab platform.
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Preparation of partially substituted 1-halo- and 1,4-dihalo-1,3-dienes via reagent-controlled Desilylation of halogenated 1,3-dienes.
The Journal of organic chemistry, 2006Co-Authors: Zhiyi Song, Guangzhen Liu, Xiaozhong Liu, Tamotsu TakahashiAbstract:Depending on the Desilylation reagents used, 1-halo-1,4-bis(trimethylsilyl)-1,3-butadienes afforded either 1-halo-1-trimethylsilyl-1,3-butadienes or 1-halo-4-trimethylsilyl-1,3-butadienes in excellent yields with excellent selectivity, respectively, when treated with CF3COOH or with NaOMe. These monosilylated 1,3-butadiene products could be further desilylated to generate their corresponding halobutadienes via the above reagent-controlled Desilylation reaction. When 1,4-dihalo-1,4-bis(trimethylsilyl)-1,3-dienes were treated with MeONa/MeOH at room temperature, Desilylation of both of the two trimethylsilyl groups took place to afford their corresponding 1,4-dihalo-1,3-dienes in excellent yields. The commonly used Desilylation reagent CF3COOH did not work for these dihalobutadienes.
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Synthesis of 1,1,4,4-Tetrabromo-2-butenes and Related Compounds via Desilylation−Bromination of Silylated 1,3-Butadiene Derivatives
The Journal of organic chemistry, 2004Co-Authors: Xiaozhong Liu, Fengyu Bao, Hongtao Fan, Tamotsu TakahashiAbstract:The combination of zirconocene-mediated coupling of silylated alkynes with a protonation-Desilylation or bromination-Desilylation process afforded otherwise unavailable butadiene derivatives. When (E,E)-2,3-dialkyl-1,4-bis(trimethylsilyl)-1,3-butadienes were treated with 3 equiv of Br(2) in CH(2)Cl(2), (E)-2,3-dialkyl-1,1,4,4-tetrabromo-2-butenes were obtained in excellent yields with perfect stereoselectivity.
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synthesis of 1 1 4 4 tetrabromo 2 butenes and related compounds via Desilylation bromination of silylated 1 3 butadiene derivatives
Journal of Organic Chemistry, 2004Co-Authors: Xiaozhong Liu, Fengyu Bao, Hongtao Fan, Tamotsu TakahashiAbstract:The combination of zirconocene-mediated coupling of silylated alkynes with a protonation-Desilylation or bromination-Desilylation process afforded otherwise unavailable butadiene derivatives. When (E,E)-2,3-dialkyl-1,4-bis(trimethylsilyl)-1,3-butadienes were treated with 3 equiv of Br(2) in CH(2)Cl(2), (E)-2,3-dialkyl-1,1,4,4-tetrabromo-2-butenes were obtained in excellent yields with perfect stereoselectivity.
Geert-jan Boons - One of the best experts on this subject based on the ideXlab platform.
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One-Pot Three-Step Synthesis of 1,2,3-Triazoles by Copper-Catalyzed Cycloaddition of Azides with Alkynes Formed by a Sonogashira Cross-Coupling and Desilylation.
ChemInform, 2011Co-Authors: Frédéric Friscourt, Geert-jan BoonsAbstract:The target triazoles can be prepared directly from aryl iodides, trimethylsilylacetylene and azides in the microwave-assisted procedure using both CuF2 or Bu4NF/CuI for the Desilylation step.
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One-Pot Three-Step Synthesis of 1,2,3-Triazoles by Copper-Catalyzed Cycloaddition of Azides with Alkynes formed by a Sonogashira Cross-Coupling and Desilylation
Organic Letters, 2010Co-Authors: Frédéric Friscourt, Geert-jan BoonsAbstract:A microwave-assisted, one-pot, three-step Sonogashira cross-coupling−Desilylation−cycloaddition sequence was developed for the convenient preparation of 1,4-disubstituted 1,2,3-triazoles starting from a range of halides, acyl chlorides, ethynyltrimethylsilane, and azides.
Laura Antonella Aronica - One of the best experts on this subject based on the ideXlab platform.
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silylation Desilylation of propargyl amides rapid synthesis of functionalised aldehydes and β lactams
Tetrahedron, 2007Co-Authors: Laura Antonella Aronica, Giulia Valentini, Anna Maria Caporusso, Piero SalvadoriAbstract:Abstract Propargyl functionalised β-silylalkenals were easily prepared starting from suitable propargyl compounds by a silylformylation process. In particular the use of propargyl tosyl amides allowed the synthesis of α,β-unsaturated aldehydes through a two-step sequence of silylformylation–Desilylation reactions. TBAF was employed to induce the Desilylation process that was performed under very mild experimental conditions and occurred along with an elimination step of the tosylamido moiety affording 2-methylaryl-2-alkenals with good yields and stereoselectivity. When the tosyl amides were reacted with a hydrosilane in the presence of catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) α-silylmethylene-β-lactams were synthesised through a silylcarbocyclisation process. A high chemoselectivity towards the β-lactam was observed when dialkyl propargyl amides were employed. The obtained β-lactams were easily transformed into the corresponding methylaryl-β-lactams by fluoride induced aryl migration–Desilylation with total retention of configuration of the migrating group and complete stereoselectivity towards the more stable β-lactam ( E )-isomer.
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Silylation–Desilylation of propargyl amides: rapid synthesis of functionalised aldehydes and β-lactams
Tetrahedron, 2007Co-Authors: Laura Antonella Aronica, Giulia Valentini, Anna Maria Caporusso, Piero SalvadoriAbstract:Abstract Propargyl functionalised β-silylalkenals were easily prepared starting from suitable propargyl compounds by a silylformylation process. In particular the use of propargyl tosyl amides allowed the synthesis of α,β-unsaturated aldehydes through a two-step sequence of silylformylation–Desilylation reactions. TBAF was employed to induce the Desilylation process that was performed under very mild experimental conditions and occurred along with an elimination step of the tosylamido moiety affording 2-methylaryl-2-alkenals with good yields and stereoselectivity. When the tosyl amides were reacted with a hydrosilane in the presence of catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) α-silylmethylene-β-lactams were synthesised through a silylcarbocyclisation process. A high chemoselectivity towards the β-lactam was observed when dialkyl propargyl amides were employed. The obtained β-lactams were easily transformed into the corresponding methylaryl-β-lactams by fluoride induced aryl migration–Desilylation with total retention of configuration of the migrating group and complete stereoselectivity towards the more stable β-lactam ( E )-isomer.
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silylformylation Desilylation of propargyl amides synthesis of α β unsaturated aldehydes
Tetrahedron Letters, 2006Co-Authors: Laura Antonella Aronica, Giulia Valentini, Anna Maria Caporusso, Patrizio Raffa, Piero SalvadoriAbstract:Abstract α,β-Unsaturated aldehydes are prepared from easily available propargyl amides through a two-step sequence of silylformylation–Desilylation reactions. The substituent on the nitrogen atom markedly influences both reactions, β-silylalkenals being formed in the presence of tosyl or tert -butoxycarbonyl protected amines. TBAF is employed to induce the Desilylation process that is performed under very mild experimental conditions. A contemporary elimination step occurs when tosylamido aldehydes are reacted affording 2-methylaryl-2-alkenals, while this process can be suppressed changing the functional group to NBOC, thus allowing the formation of β-amino carbonyl compounds.
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Silylformylation–Desilylation of propargyl amides: synthesis of α,β-unsaturated aldehydes
Tetrahedron Letters, 2006Co-Authors: Laura Antonella Aronica, Giulia Valentini, Anna Maria Caporusso, Patrizio Raffa, Piero SalvadoriAbstract:Abstract α,β-Unsaturated aldehydes are prepared from easily available propargyl amides through a two-step sequence of silylformylation–Desilylation reactions. The substituent on the nitrogen atom markedly influences both reactions, β-silylalkenals being formed in the presence of tosyl or tert -butoxycarbonyl protected amines. TBAF is employed to induce the Desilylation process that is performed under very mild experimental conditions. A contemporary elimination step occurs when tosylamido aldehydes are reacted affording 2-methylaryl-2-alkenals, while this process can be suppressed changing the functional group to NBOC, thus allowing the formation of β-amino carbonyl compounds.