Topic
Alkylation
About: Alkylation is a research topic. Over the lifetime, 29915 publications have been published within this topic receiving 464944 citations. The topic is also known as: alkylation reaction.
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TL;DR: In this article, a more efficient catalytic asymmetric Friedel-Crafts alkylation of indoles with nitroalkenes using bifunctional tridentate bis(oxazoline)-Zn(OTf)(2) as catalyst has been developed.
147 citations
TL;DR: A new model involving two regiochemically distinct (NH) and (CO) locations for nucleofuge or nucleophile binding, may prove of broad utility for the interpretation of the selectivity in asymmetric allylic alkylation reactions catalyzed by Pd complexes of (R,R)-1 and related ligands.
Abstract: The solution-phase structures of the monomeric forms of the cationic Pd-η3-allyl and Pd-η3-cyclohexenyl complexes [Pd(R,R)-1(η3-C3H5)]+ (7+) and [Pd(R,R)-1(η3-C6H9)]+ (8+) bearing the trans-cyclohexylenediamine-based Trost ‘Standard Ligand’ (R,R)-1 have been elucidated by NMR, isotopic labeling and computation. In both complexes, (R,R)-1 is found to adopt a C1-symmetric conformation, leading to a concave shape in the 13-membered chelate in which one amide group in the chiral scaffold projects its NH unit out of the concave surface in close vicinity to one allyl terminus. The adjacent amide has a reversed orientation and projects its carbonyl group out of the concave face in the vicinity of the opposite allyl terminus. Stoichiometric and catalytic asymmetric alkylations of [8+][X−] by MCHE2 (E = ester, M = ‘escort’ counterion, X = Pd allyl counterion) show the same selectivities and trends as have been reported for in situ-generated catalysts, and a new model for the enantioselectivity has been explored co...
147 citations
TL;DR: In this article, large-pore zeolites X and Y in their acidic form were explored as catalysts for isobutane/butene alkylation in order to understand the principal requirements for successful solid acid catalysts.
147 citations
TL;DR: This chapter presents physicochemical studies on hydantoins using ultraviolet spectroscopic, mass spectrometry, infrared spectroscopy, nuclear magnetic resonance spectroscope, crystal structure determinations, and quantum mechanical calculations.
Abstract: Publisher Summary This chapter reviews the chemistry of hydantoins. The hydantoins can be synthesized using amino acids, cyanate or thiocyanate salts, alkyl or aryl isocyanates and isothiocyanates, ureas, α-dicarbonyl compounds, Bucherer–Bergs and Read reactions, and cycloaddition reactions with heterocumulenes. The chapter also illustrates physicochemical studies on hydantoins. H-NMR, IR, and UV techniques are widely used to study ionization and tautomerism in hydantoins. Hydantoins are weak acids which owe their acidic character to dissociation of the proton bonded to the 3-nitrogen atom as this allows for maximum delocalization of charge in anion. The chapter also presents physicochemical studies on hydantoins using ultraviolet spectroscopy, mass spectrometry, infrared spectroscopy, nuclear magnetic resonance spectroscopy, crystal structure determinations, and quantum mechanical calculations. The reactivity of hydantoins and their derivatives are described further in the chapter. Hydantoins and thiohydantoins can react with nucleophilic and electrophilic as well as with other types of reagents. On protonation in a strongly acidic solution, hydantoin cations are formed. Hydantoins can easily be alkylated in the N-3 position by treatment with alkyl halides in an alkaline solution in protic or aprotic solvents. Other alkylating agents include dimethyl sulfate and diazomethane.
147 citations