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Phenyl Sulfone (phenyl + sulfone)

Distribution by Scientific Domains

Chemistry	71%

Selected Abstracts

Silver Acetate/TF-BiphamPhos-Catalyzed endo -Selective Enantioselective 1,3-Dipolar Cycloaddition of Azomethine Ylides with Vinyl Phenyl Sulfone

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009
Gang Liang
Abstract The first catalytic endo -selective 1,3-dipolar cycloaddition of azomethine ylides and vinyl phenyl sulfone has been developed successfully. The highly efficient silver acetate (AgOAc)/TF-BiphamPhos catalytic system exhibited high reactivity, excellent diastereoselectivity (>98:2), good enantioselectivity (67,92% ee) and broad substrate scope under mild conditions. [source]

Difluoromethyl Phenyl Sulfone, a Difluoromethylidene Equivalent: Use in the Synthesis of 1,1-Difluoro-1-alkenes.

CHEMINFORM, Issue 4 2005
G. K. Surya Prakash
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Silver Acetate/TF-BiphamPhos-Catalyzed endo -Selective Enantioselective 1,3-Dipolar Cycloaddition of Azomethine Ylides with Vinyl Phenyl Sulfone

Sulfonated poly(ether sulfone)s with binaphthyl units as proton exchange membranes for fuel cell application

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2009
Kazuya Matsumoto
Abstract Sulfonated poly(ether sulfone)s containing binaphthyl units (BNSHs) were successfully prepared for fuel cell application. BNSHs, which have very simple structures, were easily synthesized by postsulfonation of poly(1,1,-dinaphthyl ether phenyl sulfone)s and gave tough, flexible, and transparent membranes by solvent casting. The BNSH membranes showed low water uptake compared to a typical sulfonated poly(ether ether sulfone) (BPSH-40) membrane with a similar ion exchange capacity (IEC) value and water insolubility, even with a high IEC values of 3.19 mequiv/g because of their rigid and bulky structures. The BNSH-100 membrane (IEC = 3.19 mequiv/g) exhibited excellent proton conductivity, which was comparable to or even higher than that of Nafion 117, over a range of 30,95% relative humidity (RH). The excellent proton conductivity, especially under low RH conditions, suggests that the BNSH-100 membrane has excellent proton paths because of its high IEC value, and water insolubility due to the high hydrophobicity of the binaphthyl structure. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5827,5834, 2009 [source]

Structure,property correlations of sulfonated polyimides.

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 14 2004

Abstract A series of six-membered sulfonated polyimides were synthesized using 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4,-diaminobiphenyl 2,2,-disulfonic acid as the sulfonated diamine, and various nonsulfonated diamine monomers having different bridging groups. These bulky bridging groups have the capacity to increase hydrolytic stability and proton conductivity. Polyimides with bulky bridging groups showed increased solubility but exhibited lower thermal stability. The ion exchange capacity and water uptake reduced with increase in the bulkiness of the bridging group. This was attributed to the increase in the molecular weight of the repeating unit and hence effectively reduced the sulfonic acid content. In low temperatures, the conductivity was lower than Nafion®115 and, with increase in temperature, the conductivity rapidly increased and exhibited better conductivity than Nafion®115. Polyimides with bulky bridging groups 4-amino phenyl sulfone, and 2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane showed higher conductivity than other polyimides and Nafion®115 despite low ion exchange capacity. The hydrolytic stability of the polyimides with bulky bridging groups was higher than the polyimides with less bulky atoms because of the imparted flexibility. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3612,3620, 2004 [source]

Asymmetric Aza-Morita,Baylis,Hillman Reactions of Alkyl Vinyl Ketones with N -Protected Imines or In Situ Generated N -Protected Imines

EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2010
Xiao-Yang Guan
Abstract DABCO-catalyzed aza-MBH reactions of N -Boc imines with MVK and EVK have been thoroughly investigated in the paper. The asymmetric version of this aza-MBH reaction was also systematically investigated by using a chiral amine or a chiral phosphane catalyst. It was found that most of the N -protected imines are suitable substrates under the mild reaction conditions and are able to give the corresponding adducts in moderate yields with high ee values. The TQO- or LB1-catalyzed aza-MBH reactions of N -protected ,-amidoalkyl phenyl sulfones or ,-amidoalkyl p -tolyl sulfones with MVK could be well conducted, which provides a facile and direct route to obtain highly enantioselective aza-MBH adducts. The Boc protecting group of the aza-MBH product could be easily removed under acidic conditions to give the corresponding ,-methylene-,-amino ketone or ,-methylene-,-amino alcohol derivatives in good yields. [source]

Understanding Sulfone Behavior in Palladium-Catalyzed Domino Reactions with Aryl Iodides

CHEMISTRY - A EUROPEAN JOURNAL, Issue 17 2006
Inés Alonso Dr.
Abstract Unlike traditionally used acyclic 1,2-disubstituted alkenes, the reaction of ,,,-unsaturated phenyl sulfones with aryl iodides under Heck reaction conditions takes place mainly by means of a four-component domino process, involving one unit of the alkene and three units of the aryl iodide, affording substituted 9-phenylsulfonyl-9,10-dihydrophenanthrenes. We report here the results of a computational study on the mechanism of this domino arylation reaction. Based on these results we can explain why vinyl sulfones, unlike other electron-deficient alkenes such as enones, preferentially follow this domino pathway instead of the usual Heck pathway. The key step is a CH activation process in which a five-membered palladacycle is formed. The greater ability of vinyl sulfones, relative to enones, to reach the transition state that leads to the formation of the initial palladacycle makes the difference. Al contrario que los alquenos acíclicos 1,2-disustituidos tradicionalmente utilizados, la reacción de fenil sulfonas ,,, -insaturadas con yoduros de arilo bajo condiciones de reacción de Heck tiene lugar mayoritariamente a través de un proceso dominó de cuatro componentes, en el que participan una unidad de alqueno y tres unidades de yoduro de arilo, dando lugar a 9-fenilsulfonil-9,10-dihidrofenantrenos sustituidos. Aquí se presentan los resultados de un estudio computacional sobre el mecanismo de esta reacción de arilación dominó. De acuerdo con estos resultados se puede explicar por qué en el caso de las vinil sulfonas este camino de reacción predomina sobre la reacción de Heck, al contrario que en el caso de otros alquenos pobres en electrones como las enonas. La etapa clave es un proceso de activación CH en el que se forma un paladaciclo de cinco miembros. La mayor capacidad de las vinil sulfonas en comparación con las enonas para alcanzar el estado de transición que conduce al paladaciclo es la causa fundamental de este comportamiento diferencial. [source]