The Experts below are selected from a list of 111 Experts worldwide ranked by ideXlab platform
Scott E Denmark - One of the best experts on this subject based on the ideXlab platform.
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why you really should consider using palladium catalyzed cross coupling of silanols and silanolates
Organic Process Research & Development, 2015Co-Authors: Scott E Denmark, Andrea AmbrosiAbstract:The transition metal-catalyzed cross-coupling of organometallic nucleophiles derived from tin, boron, and zinc with organic electrophiles enjoys a preeminent status among modern synthetic methods for the formation of carbon–carbon bonds. In recent years, organosilanes have emerged as viable alternatives to conventional reagents, with the added benefits of low cost, low toxicity, and high chemical stability. However, silicon-based cross-coupling reactions often require heating in the presence of a fluoride source, which has significantly hampered their widespread acceptance. To address the “fluoride problem”, a new paradigm for palladium-catalyzed, silicon-based cross-coupling reactions has been developed that employs a heretofore underutilized class of silicon reagents, the Organosilanols. The use of Organosilanols, either in the presence of Bronsted bases or as their silanolate salts, represents an operationally simple and mild alternative to the fluoride-based activation method. Organosilanols are readi...
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discussion addendum for palladium catalyzed cross coupling of z 1 heptenyldimethylsilanol with 4 iodoanisole z 1 heptenyl 4 methoxybenzene
Organic Syntheses, 2012Co-Authors: Scott E Denmark, Jack Hungchang LiuAbstract:(Z)-1-heptenyldimethylsilanol 4-iodoanisole (Z)-(1-heptenyl)-4-methoxybenzene (+)-brasilenyne 1,4-bissilyl-1,3-butadiene papulacandin D Keywords: Organosilanols; palladium catalyzed cross-coupling; halides; triflates; isodomoic acids; Bronsted bases; fluoride-free alkenyl-aryl cross-coupling
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Stereospecific Palladium-Catalyzed Cross-Coupling of (E)- and (Z)-Alkenylsilanolates with Aryl Chlorides
2006Co-Authors: Scott E Denmark, Jeffrey M. KallemeynAbstract:The power and versatility of palladium-catalyzed cross-coupling reactions of organoboranes,1a-stannanes,1b and-silanes1c is attribut-able in large measure to the wide range of electrophilic coupling partners that participate in the process. In recent years the ability to engage ubiquitous and inexpensive organic chlorides has contributed significantly to the reaction scope. Thanks to advances in ligand design,2,3 cross-coupling reactions of aryl- and alkenyl-stannanes,3a,4 aryl- and alkenylsilanes,5 and arylboronic acids,3c,e,6 with aryl chlorides have been reported. However, only limited success has been obtained in the cross-coupling of alkenylboronic acids with aryl chlorides. These substrates suffer from low reactivity and, consequently, double bond isomerization during the cross-coupling reaction.3e,7 Organosilanol-based cross coupling, developed in these laboratories, has emerged as a useful method because of the high reactivity, ease of preparation, and shelf-stability of th
Tobin J Marks - One of the best experts on this subject based on the ideXlab platform.
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high performance hole transport layers for polymer light emitting diodes implementation of organosiloxane cross linking chemistry in polymeric electroluminescent devices
Journal of the American Chemical Society, 2005Co-Authors: He Yan, Paul A Lee, Neal R Armstrong, Amy L Graham, Guennadi Evmenenko, Pulak Dutta, Tobin J MarksAbstract:This contribution describes an organosiloxane cross-linking approach to robust, efficient, adherent hole-transport layers (HTLs) for polymer light-emitting diodes (PLEDs). An example is 4,4‘-bis[(p-trichlorosilylpropylphenyl)phenylamino]biphenyl (TPDSi2), which combines the hole-transporting efficiency of N,N-diphenyl-N,N-bis(3-methylphenyl)-1,1-biphenyl)-4,4-diamine) (TPD, prototypical small-molecule HTL material) and the strong cross-linking/densification tendencies of Organosilanol groups. Covalent chemical bonding of TPDSi2 to PLED anodes (e.g., indium tin oxide, ITO) and its self-cross-linking enable fabrication of three generations of insoluble PLED HTLs: (1) self-assembled monolayers (SAMs) of TPDSi2 on ITO; (2) cross-linked blend networks consisting of TPDSi2 + a hole transporting polymer (e.g., poly(9,9-dioctylfluorene-co-N-(4-(3-methylpropyl))diphenylamine), TFB) on ITO; (3) TPDSi2 + TFB blends on ITO substrates precoated with a conventional PLED HTL, poly(3,4-ethylenedioxythiophene)-poly(styre...
He Yan - One of the best experts on this subject based on the ideXlab platform.
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high performance hole transport layers for polymer light emitting diodes implementation of organosiloxane cross linking chemistry in polymeric electroluminescent devices
Journal of the American Chemical Society, 2005Co-Authors: He Yan, Paul A Lee, Neal R Armstrong, Amy L Graham, Guennadi Evmenenko, Pulak Dutta, Tobin J MarksAbstract:This contribution describes an organosiloxane cross-linking approach to robust, efficient, adherent hole-transport layers (HTLs) for polymer light-emitting diodes (PLEDs). An example is 4,4‘-bis[(p-trichlorosilylpropylphenyl)phenylamino]biphenyl (TPDSi2), which combines the hole-transporting efficiency of N,N-diphenyl-N,N-bis(3-methylphenyl)-1,1-biphenyl)-4,4-diamine) (TPD, prototypical small-molecule HTL material) and the strong cross-linking/densification tendencies of Organosilanol groups. Covalent chemical bonding of TPDSi2 to PLED anodes (e.g., indium tin oxide, ITO) and its self-cross-linking enable fabrication of three generations of insoluble PLED HTLs: (1) self-assembled monolayers (SAMs) of TPDSi2 on ITO; (2) cross-linked blend networks consisting of TPDSi2 + a hole transporting polymer (e.g., poly(9,9-dioctylfluorene-co-N-(4-(3-methylpropyl))diphenylamine), TFB) on ITO; (3) TPDSi2 + TFB blends on ITO substrates precoated with a conventional PLED HTL, poly(3,4-ethylenedioxythiophene)-poly(styre...
Andrea Ambrosi - One of the best experts on this subject based on the ideXlab platform.
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why you really should consider using palladium catalyzed cross coupling of silanols and silanolates
Organic Process Research & Development, 2015Co-Authors: Scott E Denmark, Andrea AmbrosiAbstract:The transition metal-catalyzed cross-coupling of organometallic nucleophiles derived from tin, boron, and zinc with organic electrophiles enjoys a preeminent status among modern synthetic methods for the formation of carbon–carbon bonds. In recent years, organosilanes have emerged as viable alternatives to conventional reagents, with the added benefits of low cost, low toxicity, and high chemical stability. However, silicon-based cross-coupling reactions often require heating in the presence of a fluoride source, which has significantly hampered their widespread acceptance. To address the “fluoride problem”, a new paradigm for palladium-catalyzed, silicon-based cross-coupling reactions has been developed that employs a heretofore underutilized class of silicon reagents, the Organosilanols. The use of Organosilanols, either in the presence of Bronsted bases or as their silanolate salts, represents an operationally simple and mild alternative to the fluoride-based activation method. Organosilanols are readi...
Jack Hungchang Liu - One of the best experts on this subject based on the ideXlab platform.
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discussion addendum for palladium catalyzed cross coupling of z 1 heptenyldimethylsilanol with 4 iodoanisole z 1 heptenyl 4 methoxybenzene
Organic Syntheses, 2012Co-Authors: Scott E Denmark, Jack Hungchang LiuAbstract:(Z)-1-heptenyldimethylsilanol 4-iodoanisole (Z)-(1-heptenyl)-4-methoxybenzene (+)-brasilenyne 1,4-bissilyl-1,3-butadiene papulacandin D Keywords: Organosilanols; palladium catalyzed cross-coupling; halides; triflates; isodomoic acids; Bronsted bases; fluoride-free alkenyl-aryl cross-coupling