Showing papers on "Aryl radical published in 2006"

Controlling the regiochemistry of radical cyclizations

Abstract: This review describes the results of our recent studies on the control of the regiochemistry of radical cyclizations. N-vinylic α-chloroacetamides generally cyclized in a 5-endo-trig manner to give five-membered lactams, whereas 4-exo-trig cyclization occurred when the cyclized radical intermediates were highly stabilized by an adjacent phenyl or phenylthio group to afford β-lactams. The 5-exo or 6-exo cyclization of aryl radicals onto the alkenic bond of enamides could be shifted to the corresponding 6-endo or 7-endo mode of cyclization by a positional change of the carbonyl group of enamides. The 6-endo- and 7-endo-selective aryl radical cyclizations were applied to radical cascades for the synthesis of alkaloids such as phenanthroindolizidine, cephalotaxine skeleton, and lennoxamine. The 5-exo-trig cyclization of an alkyl radical onto the alkenyl bond of enamides could also be shifted to the 6-endo mode by a positional change of the carbonyl group of enamides. The 6-endo- selective cyclization was applied to the radical cascade to afford a cylindricine skeleton. Other examples of controlling the regiochemistry of radical cyclizations and their applications to the synthesis of natural products are also discussed. © 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 23–31; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20069

Radicals in Synthesis II

Abstract: Siegfried R Waldvogel Stamo Mentizi Axel Kirste Boron-Doped Diamond Electrodes for Electroorganic Chemistry- Gerald Pratsch Markus R Heinrich Modern Developments in Aryl Radical Chemistry- Gregory K Friestad Radical Additions to Chiral Hydrazones: Stereoselectivity and Functional Group Compatibility- Andreas Gansauer Lei Shi Matthias Otte Inga Huth Antonio Rosales Iris Sancho-Sanz Natalia M Padial J Enrique Oltra Hydrogen Atom Donors: Recent Developments- Ullrich Jahn Radicals in Transition Metal Catalyzed Reactions? Transition Metal Catalyzed Radical Reactions? - A Fruitful Interplay Anyway Part 1 Radical Catalysis by Group 4 to Group 7 Elements- Ullrich Jahn Radicals in Transition Metal Catalyzed Reactions? Transition Metal Catalyzed Radical Reactions? - A Fruitful Interplay Anyway Part 2 Radical Catalysis by Group 8 and 9 Elements- Ullrich Jahn Radicals in Transition Metal Catalyzed Reactions? Transition Metal Catalyzed Radical Reactions?: A Fruitful Interplay Anyway Part 3: Catalysis by Group 10 and 11 Elements and Bimetallic Catalysis

Process for production a thin glasslike coating on substrates for reducing gas permeation

Abstract: A method for producing a glassy, transparent coating on a substrate by coating the substrate with a solution containing a) a polysilazane of the formula —(SiR′R″—NR′″) n — where R′, R″, R′″ are identical or different and independently represent hydrogen or an optionally substituted alkyl radical, aryl radical, vinyl radical or (trialkoxysilyl)alkyl radical, n being an integer and or being calculated such that the polysilazane has a number-average molecular weight of from 150 to 150 000 g/mol, and b) a catalyst in an organic solvent, removing the solvent using evaporation such that a polysilazane layer having a layer thickness of 0.05-3.0 μm remains on the substrate, and irradiating the polysilazane layer with VUV radiation having wavelength portions <230 nm and UV radiation having wavelength portions between 230 and 300 nm in an atmosphere containing steam in the presence of oxygen, active oxygen and optional nitrogen.

Infrared dye compositions

Abstract: Disclosed are novel aminium, diimonium, and polymethine borate dyes that have at least one absorption maximum in the infrared spectral region between about 700 and 2000 nm and that are useful as infrared absorbers, the anionic borate moiety having the formula: [BXaYb]- in which a and b are integers with a ranging from 0 to 3 and b ranging from 1 to 4 and a + b = 4; X, which may be identical or different, are each a halogen atom, an OH functional group, or a C1 to C20 alkyl or alicyclic radical, and Y, which may be identical or different, are each a phenyl radical, at least one Y substituted by at least one element or electron-withdrawing substituent such as a perfluoroalkyl group, or by one or more halogen atoms, or an aryl radical containing at least two aromatic ring members, which may also be further substituted. Such dyes may be incorporated into films or bulk materials to form light filters for electromagnetic radiation, including laser radiation.

Binding agents having barrier properties

Abstract: The invention relates to binding agents having barrier properties, containing: a) a compound having at least one NCO group and at least one reactive functional group, which can be cured by radiation and which serves as component (A), and; b) a silicon-organic compound serving as component (B) with at least one NCO group and at least one functional group of formula (I): -Si(X)3-n , in which X represents -NH2; -NH-CO-R; -OOC-R; -O-N=C(R)2 or OR'; R represents a linear or branched, saturated or unsaturated C1-C18 alkyl radical, preferably a methyl, ethyl, propyl or isopropyl radical; R' represents R, preferably a methyl, ethyl, propyl or isopropyl radical or an oxyalkylene radical having up to 4 C atoms, preferably -(C2H4-O)m-H and/or (CH2-CH(CH3)-O)m-H, a C5-C8 cycloalkyl radical; a C6-C10 aryl radical or a C7-C12 aralkyl radical; m equals 1 to 40, preferably 1 to 20, particularly preferred 1 to 10; n equals 0, 1 or 2. The binding agent is used a radiation curable binding agent in coating agents, fillers, sealants or adhesives. The invention also relates to a method for producing laminated films having barrier properties with regard to CO2, O2, N2, water vapor and flavoring agents while using the inventive binding agent, and to the laminated films produced according to said method.

Particles comprising zwitterionic structural elements

Abstract: The invention relates to particles (PS) comprising at least one structural element selected among general formulas [1] to [3], -NR2+-B-A- [1], =NR+-B-A- [2], =N+-B-A- [3], and the protonated and deprotonated forms of the structural elements of general formulas [1] to [3], wherein A represents an -SO3 sulfonate radical, a -C(O)O carboxylate radical, or a -P(O)(OR7)O phosphonate radical, B represents (CR12)m, an optionally substituted alkyl radical, aryl radical, or heteroaryl radical interrupted by heteroatoms, R and R7 represent hydrogen or an optionally substituted hydrocarbon radical, R1 represents hydrogen, halogens, or an optionally substituted hydrocarbon radical, and m can have the values 1, 2, 3, 4, or 5, provided that the nitrogen atom in general formula [2] is part of an aliphatic heterocycle as an endocyclic nitrogen atom, and provided that the nitrogen atom in general formula [3] is part of an aromatic heterocycle as an endocyclic nitrogen atom.

Haircare Use Of C-Glycoside Derivatives

Abstract: The present invention relates to the cosmetic use of at least one compound of general formula (I), in which: - X represents a radical chosen from the groups, with R1, R2 and R3 representing, independently of each other, a hydrogen atom, an OH group or a radical R with R as defined below, - R represents an alkyl radical, a polyfluoroalkyl or perfluoroalkyl radical or an aryl radical, - S represents a monosaccharide or a polysaccharide comprising upto 20 sugar units, in pyranose and/or furanose form and of L and/or D series, and - the bond S-C represents a bond of C-anomeric nature, or a salt or isomer thereof, for increasing the mechanical strength of keratin fibers.

Catalyst components for olefinic polyreaction and catalyst thereof

Abstract: the invention provides a catalyst component for CH2u¢CHR olefin polymerization reaction and its catalyst, wherein R is hydrogen or C1-C6 alkyl or aryl radical; such component comprising magnesium, titanium, halogen and electron donor, such electron donor is more than one kind diester of such formula (I), wherein Rio is the same with or different from R1, extracted from C1-C20 alkyl, cycloalkyl, aryl radical, alkylaryl, aralkyl, alkylene, condensed-nuclei aryl radical of substituted or unsubstituted straight/branched chain; such catalyst can be used for propylene polymerization, to get satisfied productivity, and high stereospecificity of polymers, with wide molecular weight distribution, which is good for developing polymers with different brands.

Method for the production of a thin glassy coating on substrates in order to reduce gas permeation

Abstract: Disclosed is a method for producing a glassy, transparent coating on a substrate by coating the substrate with a solution containing a) a polysilazane of formula -(SiR'R'-NR'')n-, wherein R', R', R'' are identical or different and independently represent hydrogen or an optionally substituted alkyl radical, aryl radical, vinyl radical, or (trialkoxysilyl)alkyl radical, n being an integer or being calculated such that the polysilazane has a number-average molecular weight ranging from 150 to 150,000 g/mol, and b) a catalyst in an organic solvent, and then removing the solvent using evaporation such that a polysilazane layer having a thickness of 0.05 to 3.0 µm remains on the substrate, and irradiating the polysilazane layer with VUV radiation having wavelength portions < 230 nm and UV radiation having wavelength portions ranging between 230 and 300 nm in an atmosphere containing steam in the presence of oxygen, active oxygen, and optional nitrogen.

Method for obtaining highly luminescent lanthanide complexes

Abstract: The invention concerns a transition metal coordination complex of general formula (I) {[M(X)]C(H2O)n}p wherein: M represents an element belonging to the lanthanide group; L represents a decadentate chromophore ligand of general formula (II), wherein: R1, R2, R3 and R4 independently represent hydrogen or an alkyl or aryl radical; A1, A2, A3 and A4 independently represent a structure of general formula (III), wherein: U1, U2 and U3 independently represent C or N; R5, R6 and R7 independently represent hydrogen, an alkyl or aryl radical; Y represents C, O, S, P or N; m is an integer representing the number of free valences of Y; R8 represents independently hydrogen, an alkyl or aryl radical; X represents a counter-ion; n represents the number of hydrating water molecules; p represents the number of monomers; H2O represents the hydrating water molecules. The invention also concerns a method for preparing a ligand by reaction between a 6-chloromethylpyridine-2-carboxylate ethyl ester and ethylenediamine in organic medium, as well as a method for preparing a coordination complex by reaction between a lanthanide chloride and a ligand in aqueous medium. The invention further concerns the use of such a coordination complex in medicine, as markers for luminescence imaging, in the development of luminescent probes for medical imaging and bioassays and in the development of novel materials for nanotechnologies.

Thermochromic and thermoflourescent pigments: enhancing color and flourescence with additives

Abstract: A thermal indicator material and method of producing a material capable of a thermochromic transition upon undergoing a temperature change. The material comprises a plurality of compounds having the following structure: (I) wherein R1-R6 = a hydrogen, substituted or unsubstituted alkyl radical, substituted or unsubstituted alkoxy radical, substituted or unsubstituted aryl radical, substituted or unsubstituted thioalkyl radical, substituted or unsubstituted trialkylsilyl radical, substituted or unsubstituted acyl radical, substituted or unsubstituted ester radical, substituted or unsubstituted amine radical, substituted or unsubstituted amide radical, substituted or unsubstituted heteroaryl or substituted or unsubstituted aryl radical n is between 1 and 1000, m is between 0 and 1000, and 1 is between 1 and 1000; with added small molecules, the small molecule additive having the following structure: R-Ar-R' , R-X, linaer alkane, or oligoethylene oxide small molecules with molecular weight less than 1,000 AMU wherein R-R' = a hydrogen, substituted or unsubstituted alkyl radical, substituted or unsubstituted alkoxy radical, substituted or unsubstituted thioalkyl radical, substituted or unsubstituted trialkylsilyl radical, substituted or unsubstituted acyl radical, substituted or unsubstituted ester radical, substituted or unsubstituted amine radical, substituted or unsubstituted amide radical, substituted or unsubstituted heteroaryl or substituted or unsubstituted aryl radical and Ar = a substituted or unsubstituted aromatic or heteroaromatic radical including but not limited to benzene, thiophene, naphthalene, flourene, anthracene, pyridine, indine, biphenyl, phenanthrene, and furan X = a halogen (F, Cl, Br, or I). The thermochromic transition of the material is reversible. The thermochromic transition is a two step transition, such that when the samples are heated above the thermochromic transition temperature followed by a rapid cooling to a temperature below the thermochromic transition temperature in a time of less than about 5 seconds, a new low temperature color is generated which then has an irreversible thermochromic transition.

Novel dual peptidase inhibitors as prodrugs for the therapy of inflammatory and other disorders

Abstract: The invention relates to compounds of the general formulae (1) and (2) A - B - D - B' - A' (1) and A - B - D - E (2), in which A and A' may be identical or different and are the radical (I) in which X is S, O, CH2, CH2CH2, CH2O or CH2NH, and Y is H or CN, and * designates a chiral carbon atom, preferably in the S or L configuration; B and B' may be identical or different and are an O-, N- or S-containing or non-O-, N- or S-containing, unsubstituted or substituted, unbranched or branched alkylene radical, cycloalkylene radical, aralkylene radical, heterocycloalkylene radical, heteroarylalkylene radical, arylamidoalkylene radical, heteroarylamidoalkylene radical, unsubstituted or mono- or polysubstituted arylene radical or heteroarylene radical having one or more five-, six- or seven-membered ring(s); D is -S-S- or -Se-Se-; and E is the group -CH2-CH(NH2)-R9 or -CH2-*CH(NH2)-R9 in which R9 is an O-, N- or S-containing or non-O-, N- or S-containing, unsubstituted or substituted, unbranched or branched alkyl radical, cycloalkyl radical, aralkyl radical, heterocycloalkyl radical, heteroarylalkyl radical, arylamidoalkyl radical, heteroarylamidoalkyl radical, unsubstituted or mono- or polysubstituted aryl radical or heteroaryl radical having one or more five-, six- or seven-membered rings and * designates a chiral carbon atom preferably in the S or L configuration; or the acid addition salts thereof with organic and/or inorganic acids; and the use of the compounds of the general formulae (1) and (2) in medicine.

Method for producing single enantiomer epoxides by the adh reduction of alpha-leaving group-substituted ketones and cyclisation

Abstract: The invention relates to a method for producing single enantiomer epoxides by reducing a-leaving group-substituted ketones with (R)- or (S)-selective alcohol dehydrogenases in the presence of a cofactor and optionally a suitable system for regenerating the oxidised cofactor, to produce the corresponding single enantiomer alcohols and subsequently, by means of cyclisation induced by a base, the corresponding single enantiomer epoxides (EQUATION 1 ), wherein in EQUATION 1 LG may stand for F, CI, Br, I, OSO2Ar, OSO2CH3, OSO2R or OP(O)OR2, and R1, R2 and R3, independently of one another, stand for hydrogen, a branched or unbranched, optionally substituted C1-C2O- alkyl radical, symbolise an optionally randomly substituted C3-C10- cycloalkyl or alkenyl radical or a randomly substituted carbo- or heterocyclic aryl radical, or corresponds to a radical from the group CO2R, CONR2, COSR, CS2R, C(NH)NR2, CN, CHaI3, ArO, ArS, RO, RS, CHO, OH, NHR, NR2, Cl, F, Br, I or SiR3.

Process for preparing 1,1,4,4-tetraalkoxybut-2-ene derivatives

Abstract: Process for preparing 1,1,4,4-tetraalkoxybut-2-ene derivatives of the general formula (I), where the radicals R 1 and R 2 are each, independently of one another, hydrogen, C 1 -C 6 -alkyl, C 6 -C 12 -aryl, such as phenyl, or C 5 -C 12 -cycloalkyl or R 1 and R 2 together with the double bond to which they are bound form a C 6 -C 12 -aryl radical, such as phenyl, a phenyl radical substituted by one or more C 1 -C 6 -alkyl groups, halogen atoms or alkoxy groups or a monounsaturated or polyunsaturated C 5 -C 12 -cycloalkyl radical, R 3 , R 4 are each, independently of one another, hydrogen, methyl, trifluoromethyl or nitrile, which comprises electrochemically oxidizing 1,4-dialkoxy-1,3-butadiene of the formula II where the radicals R 1 , R 3 and R 4 have the same meanings as in the formula I, in the presence of a C 1 -C 6 -alkyl alcohol.

Synthesis of 3,3-Disubstituted 2,3-Dihydrobenzofuran Derivatives from Baylis—Hillman Adducts.

Abstract: Dihydrobenzofuran derivatives are important synthetic intermediates and showed many biologically interesting activities. However, synthetic methods for the compounds are rather limited. Recently Trost and co-workers have reported the synthesis of dihydrobenzofuran derivatives starting from the Baylis-Hillman adducts by using the reductive Heck-type cyclization strategy. Very recently, Lamaty and co-workers reported the synthesis of 3,3disubstituted-2,3-dihydrobenzofuran derivatives via palladium-catalyzed cascade allylation-carbopalladation-Suzuki cross coupling strategy. On the other hand, Shanmugam and Rajasingh have reported the synthesis of tetrahydrofuran backbone by the radical cyclization of triple bond containing cinnamate derivatives, which were synthesized from the BaylisHillman adducts. They used vinyl radical, which was formed via the in situ hydrostannylation of triple bond. We were stimulated by the results and envisioned that we could prepare 2,3-dihydrobenzofuran skeleton if we use aryl radical instead of the vinyl radical as shown in Scheme 1. Thus, we prepared the starting material 3a from the reaction of the acetate of Baylis-Hillman adduct 1a and 2bromophenol (2a) as shown in Scheme 1. The starting material 3a was converted to the desired 2-benzyl-2,3dihydrobenzofuran-2-carboxylic acid methyl ester (4a), the 5-exo-trig cyclization product, in 79% yield under the influence of n-Bu3SnH/AIBN in benzene at refluxing temperature (entry 1 in Table 1). We could not isolate the corresponding dihydrobenzopyran derivative, the 6-endotrig cyclization product, or simple reduction product. The optimum amounts of n-Bu3SnH and AIBN were studied and

Síntese de aliloxi-orto-iodobenzamida derivada de d-glicose e reação de ciclização radicalar mediada por hidreto de tri-n-butilestanho

Abstract: Methyl 6-O-allyl-2,3-di-O-benzyl-4-deoxy-4-(2 -iodobenzoylamine)-a-D-glucopyranoside was synthesized in nine conventional steps from methyl a-D-glucopyranoside. Its Bu3SnH-mediated aryl radical cyclization provided a benzomacrolactam, resulting from 11-endo aryl radical cyclization and the reduced uncyclized product methyl 6-O-allyl-4-benzoylamine-2,3-di-O-benzyl-4-deoxy- a-D-glucopyranoside. The structures of the three new products were supported by 1H and 13C NMR spectroscopy and DEPT, COSY and HMQC experiments.

Mixture of substances for treating invertebrate and vertebrate parasites that attack animals

Abstract: The invention relates to a mixture of substances, in particular a biocide for combating human and animal parasites comprising a) an A component containing at least one type of alcohol of general formula R1-OH or R1-OH-R1', wherein R1 and/or R1' is an alkyl radical associated with a hydroxyl group which comprises from 1 to 12, preferably from 1 to 6, carbon atoms, b) a B component consisting of at least one type of carbonyl compound of formula R2-CO-R2', wherein R2 and/or R2' is an aryl-, alkyl- or cycloalkyl radical associated with a carbonyl group containing from 1 to 5, preferably from 1 to 2, carbon or hydrogen atoms, and c) at least one type of essential oil in the form of a C component consisting of an aromatic hydroxy compound of formula R3-0H, wherein R3 is a compound of at least one type of cyclic aryl radical which can be substituted up to two times and at least one organic compound R3', wherein R3' is an aryl-, alkyl- or cycloalkyl radical, wherein The components A and B are brought into reaction with hydrogen peroxide and the component C is subsequently mixed.

Rubbery graft copolymers having improved resistance against thermooxidative degradation

Abstract: Graft rubbers, which are stabilized to degradation by thermal oxidation, contains a phenolic compound (A) having at least one specific structural unit (I), and a sulfur-containing synergistic agent (B) having at least one structural unit (II). The agent (B) is obtained by polymerization of optionally substituted styrene with optionally substituted acrylonitrile and mercaptan. Graft rubbers, which are stabilized to degradation by thermal oxidation, contains a phenolic compound (A) having at least one structural unit of formula (I), and a sulfur-containing synergistic agent (B) having at least one structural unit of formula (II). The agent (B) is obtained by polymerization of optionally substituted styrene with optionally substituted acrylonitrile and mercaptan (HSR 6>). R 1>-R 4>,R 6>optionally substituted 1-20C hydrocarbon radical; R 5>optionally substituted 1-20C hydrocarbon radical, or together with radical of compound (A), forms optionally substituted carbocyclic radical;and R : C 6H 5, -CN or substituted aryl radical. An independent claim is included for preparation of dried graft polymers, which involves adding phenolic compound contained in aqueous emulsion or dispersion form and synergistic agent contained in aqueous emulsion to graft rubber contained in emulsion form, before working up and drying by a fluid-bed dryer, a fluidized-bed dryer, a pneumatic dryer or kneaded reactor with styrene. [Image].

Radical Dearomatization of Arenes and Heteroarenes.

Abstract: The stannane-mediated benzeneselenol-catalyzed addition of aryl iodides to a range of arenes and aromatic hetereocycles has been studied. With furan, thiophene, and several carbocyclic arenes, the addition takes place with quenching of the adduct radical by the catalytic selenol leading to moderate yields of aryl-dihydroarenes. With nitrogen heterocycles, on the other hand, it was not possible to suppress aromatization of the adduct radical and fully aromatized products were isolated. Aryl iodides bearing hydrogen bond donating groups in the ortho-position add to nitrogen heterocycles with high selectivity ortho- to the nitrogen, affording a simple one-step synthesis of potential chelating ligands. While 2-iodophenol is an excellent aryl radical source in these reactions, the homologous 1-iodo-2-naphthol fails owing to its reaction with diphenyl diselenide, which gives 1-phenylseleno-2-naphthol in high yield.

Process for the coupling of benzylamines and halogenated aromates

Abstract: Preparing optionally substituted arylated benzylamines comprises reacting optionally substituted benzylamines with optionally substituted aryl halides. The reaction is effected in the presence of palladium complex bearing bisaryldialkylphosphine compound(s) as ligand, in the presence of mixtures of organic solvents comprising optionally substituted aromatic hydrocarbons and polar solvent(s) and in the presence of alkali metal or alkaline earth metal-containing base(s). Preparing optionally substituted arylated benzylamines of formula (I) comprises reacting optionally substituted benzylamines of formula (II) with optionally substituted aryl halides of formula (III). The reaction is effected in the presence of palladium complex bearing bisaryldialkylphosphine compound(s) of formula (IV) as ligand, in the presence of mixtures of organic solvents comprising optionally substituted aromatic hydrocarbons and polar solvent(s) and in the presence of alkali metal or alkaline earth metal-containing base(s). R 1>-R 10>H, 1-12C alkyl or (fluoro)alkoxy, 4-18C aryl, 5-19C arylalkyl, nitrile, ester, amide, ketone, aldehyde, OH, COOH, or F; X : Cl, Br or I; R 11>, R 12>1-12C alkyl or 5-19C arylalkyl; R 13>, R 14>H or 1-6C alkyl, dialkylamino or alkoxy; R 15>H, 1-12C (fluoro)alkyl or (fluoro)alkoxy, F, 4-18C aryl, or 5-19C arylalkyl, where the arrows indicate the possible bonding sites to the particular aryl radical; and n, m : 0-3. [Image] [Image].

Ppar activator derivatives, preparation method thereof and use of same in therapeutics

Abstract: The invention relates to compounds having formula (I), in which: A represents -(C C)- or -(CH2)m-, wherein m is 1, 2 or 3; Y is a hydrogen atom or a hydroxyl radical or forms a double bond with X1 or X2; X1 and X2 represent -(CH2)n-, wherein n is 0, 1, 2 or 3, or a (=CH-) group, on the condition that X1 and X2 do not simultaneously represent a (=CH-) group; R1 and R2 represent a linear or branched alkyl group with between 1 and 8 carbon atoms or an aryl radical, with the provision that, when A is -(CH2)m-, X1R1 and X2R2 each comprise at least 3 carbon atoms; Z represents an oxygen, a sulphur atom or -(CH2)-; and R3, R4 and R5 represent a hydrogen atom or a lower alkyl group with between 1 and 6 carbon atoms. The invention also relates to the use of said compounds in therapeutics for the treatment of certain hyperlipidemias and atherosclerosis.

Controlling the Regiochemistry of Radical Cyclizations

Abstract: This review describes the results of our recent studies on the control of the regiochemistry of radical cyclizations. N-vinylic α-chloroacetamides generally cyclized in a 5-endo-trig manner to give five-membered lactams, whereas 4-exo-trig cyclization occurred when the cyclized radical intermediates were highly stabilized by an adjacent phenyl or phenylthio group to afford β-lactams. The 5-exo or 6-exo cyclization of aryl radicals onto the alkenic bond of enamides could be shifted to the corresponding 6-endo or 7-endo mode of cyclization by a positional change of the carbonyl group of enamides. The 6-endo- and 7-endo-selective aryl radical cyclizations were applied to radical cascades for the synthesis of alkaloids such as phenanthroindolizidine, cephalotaxine skeleton, and lennoxamine. The 5-exo-trig cyclization of an alkyl radical onto the alkenyl bond of enamides could also be shifted to the 6-endo mode by a positional change of the carbonyl group of enamides. The 6-endo- selective cyclization was applied to the radical cascade to afford a cylindricine skeleton. Other examples of controlling the regiochemistry of radical cyclizations and their applications to the synthesis of natural products are also discussed. © 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 23–31; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20069

Relaying Asymmetry of Transient Atropisomers of o-Iodoanilides by Radical Cyclizations.

Abstract: Atropisomers of N-2 degrees -alkyl-N-acryloyl-2-iodoanlides have been resolved by chromatography and crystallization-induced asymmetric transformation. These molecules have atropisomerization barriers of 23-24 kcal/mol and return to equilibrium ratios over several hours at ambient temperature in solution. The transient chirality can be locked in by radical cyclizations, which provide N-2 degrees -alkyl-3-methyl-1,3-dihydroindol-2-ones with high levels of chirality transfer. The mechanistic model features a stereoselective aryl radical cyclization that is more rapid than the rotation of the N-aryl bond of the anilide.

Method for the production of magnesium alkoxide granules, and use thereof

Abstract: This invention relates to a process for preparing magnesium alkoxide granulates. The process includes the steps of reacting magnesium metal with at least one compound of formula AlR 3-n Hal n and an alcohol in a non-coordinating solvent. R is an alkyl or aryl radical, Hal is a halogen radical and n is in the range of between 0 and 2.

Transition metal complexes and catalyst compositions containing them

Abstract: Transition metal complex of Formula 1: wherein R a C1-C20 alkyl, aryl, or silyl; a C1-C20 alkenyl, alkylaryl, or arylalkyl; or a metalloid of a metal of Group 14 substituted with a hydrocarbon, where R may be linked together through an alkylidene R a halogen; or a C1-C20 alkyl or aryl radical, wherein two R R a C1-C20-alkylcarbonyl, arylcarbonyl or silyl carbonyl radical; C1-C20-alkylcarboxy or arylcarboxy is; M is a transition metal of Group 4; ...