Search results for "Crafts"

Enantioselective Synthesis of Substituted Indoles Through Zirconium(IV)-Catalyzed Friedel–Crafts Alkylation

2012

The chiral complex of ( R )-3,3′-Br 2 -BINOL and zirconium tert -butoxide catalyzes the Friedel–Crafts alkylation of indoles with enones bearing an alkyl or fluorinated group at the β-position to give indoles having a side chain at the C3 position with a tertiary stereogenic center in good yields and with excellent enantioselectivities.

1975

In the polymerization of isobutene catalyzed by aluminium tribromide and in the polymerization of styrene catalyzed by trifluoromethanesulphonic acid it is supposed that an inactive catalyst monomer complex is formed which is in equilibrium with other active species. The monomer complexation of the catalyst explains the S-shaped conversion curves and the complex kinetics of the polymerization. The value of the equilibrium constant Km (complexation constant) expresses what part of the catalyst may take part in the polymerization process as an active initiating species. For the system isobutene/AlBr3, Km was found to be 0,62 1/mol. In the system styrene/CF3SO3H, the high value of the complexa…

Organocatalytic enantioselective aza-Friedel–Crafts reaction of 2-naphthols with benzoxathiazine 2,2-dioxides

2015

An organocatalytic enantioselective aza-Friedel–Crafts addition of 2-naphthols to benzoxathiazine 2,2-dioxides is described using a quinine-derived bifunctional catalyst. The method allows the use of a wide range of aromatic compounds as nucleophiles, including 1-naphthol and sesamol, and benzoxathiazines 2,2-dioxides, expanding the existing state of the art enantioselective synthesis of aminomethylnaphthol derivatives.

ChemInform Abstract: Organocatalytic Enantioselective Aza-Friedel-Crafts Reaction of 2-Naphthols with Benzoxathiazine 2,2-Dioxides.

2015

An organocatalytic enantioselective aza-Friedel–Crafts addition of 2-naphthols to benzoxathiazine 2,2-dioxides is described using a quinine-derived bifunctional catalyst. The method allows the use of a wide range of aromatic compounds as nucleophiles, including 1-naphthol and sesamol, and benzoxathiazines 2,2-dioxides, expanding the existing state of the art enantioselective synthesis of aminomethylnaphthol derivatives.

ChemInform Abstract: Catalytic Enantioselective Friedel-Crafts Reactions of Naphthols and Electron-Rich Phenols

2016

The enantioselective Friedel–Crafts reaction is a powerful tool for the construction of benzylic stereocenters in a stereodefined manner. Significant advances have already been achieved with heteroarenes such as indoles and pyrroles; however, the reaction with homoarenes is less developed. This short review covers the most relevant literature on enantioselective Friedel–Crafts reactions with naphthols and phenols. 1 Introduction 2 Friedel–Crafts Reactions Involving 1,2-Nucleophilic Addition to C=X Bonds 3 Friedel–Crafts Reactions Involving Conjugate Nucleophilic Addition to Electrophilic C=C Bonds 4 Friedel–Crafts Reactions Involving π-Allylic Complexes as Electrophiles 5 ipso-Friedel–Craft…

ChemInform Abstract: Enantioselective Zirconium-Catalyzed Friedel-Crafts Alkylation of Pyrrole with Trifluoromethyl Ketones.

2009

The first catalytic enantioselective Friedel−Crafts alkylation of pyrrole with 2,2,2-trifluoroacetophenones to give pyrroles with a trifluoromethyl-substituted tertiary alcohol moiety bearing a quaternary stereogenic center is described. The reaction is achieved in the presence of a 3,3′-dibromo-BINOL-Zr(IV) complex to give the expected products with high yields (up to 98%) and good enantioselectivities (up to 93% ee). The absolute stereochemistry of the products has been determined by chemical correlation.

Dimethoxy Aromatic Compounds. VIII. Degenerate Dealkylation-Realkylation Reaction of 1-Bis(2,4-dimethoxyphenyl)-2-methylpropane.

1994

The condensation reaction under acid condition of the benzylic alcohols 1, 2 and 3 with the hexadeutero dimethoxybenzenes 4, 5 and 6 leads to the expected hexadeutero bis(dimethoxyphenyl)-2-methylpropanes 7, 8 and 9, respectively. However, the presence of both dodecadeutero and unlabelled 1-bis(2, 4-dimethoxyphenyl)-2-methylpropanes 10 and 11 indicates that 9 undergoes a rapid degenerate dealkylation-alkylation reaction.

Construction Guilds in Southern Italy and the Islands (15th-16th Centuries): Leadership and Rivalries

2020

In the South of Italy and the big islands, in counter-trend with respect to the rest of the peninsula, construction guilds know a renewed vitality between the last decades of 15th and the beginning of 16th centuries. Rules, prerogatives and operative modes are regulated by statutes, often undersigned by the masters included in the trade organization, mentioning also the other actors involved in the approval processes. The intertwining of these and other archival documents sometimes reveals the leading role played within the guild by masters that overcome the anonymity usually considered to be inherent in the corporate system. Comparing the rules and the boundaries among specific trades esta…

Beyond Health and Happiness : An Exploratory Study Into the Relationship Between Craftsmanship and Meaningfulness of Sport

2021

Meaning in movement is an enduring topic in sport social sciences, but few studies have explored how sport is meaningful and for whom. The authors examined the relationships between demographic variables, meaningfulness of sport, and craftsmanship. Athletes (N = 258, 61.6% male, age ≥18) from the United Kingdom completed a demographic questionnaire, the Work and Meaning Inventory modified for sport, and the Craftsmanship Scale. Older age and individual sport significantly correlated with higher craftsmanship. Craftsmanship and religion were two independent predictors of meaningfulness, but emphasized somewhat different meaning dimensions. Meaningfulness in sport seems to be related to how a…

Fontaines (Saône-et-Loire). Place de l’Église [notice archéologique]

2019

Le village actuel de Fontaines, situé à environ 8 km au N.-O. de Chalon-sur-Saône, se développe sur 1,5 km de long selon un unique axe E-O, depuis la montagne Saint-Hilaire à l’ouest, occupée au Néolithique puis durant l’Antiquité tardive et le haut Moyen Âge, jusqu’à l’église paroissiale Saint-Just, à l’est. Malgré une emprise limitée et contrainte par de nombreux réseaux existants, l’opération a permis de documenter l’environnement immédiat de l’église, occupé depuis l’Antiquité jusqu’à nos jours.