Alkyl Tosylates Research Articles

ChemInform Abstract: Iron‐Catalyzed Directed Alkylation of Aromatic and Olefinic Carboxamides with Primary and Secondary Alkyl Tosylates, Mesylates, and Halides.

Alkenes, arenes, and heteroarenes possessing an 8-quinolylamide group as the directing group are alkylated with primary and secondary alkyl tosylates, mesylate, and halides in the presence of Fe(acac)3/diphosphine as a catalyst and ArZnBr as a base. The reaction proceeds stereospecifically for alkene substrates and takes place without loss of regiochemical integrity of the starting secondary tosylate, but with loss of the stereochemistry of the chiral center.

Engaging nonaromatic, heterocyclic tosylates in reductive cross-coupling with aryl and heteroaryl bromides.

A method has been developed for the introduction of nonaromatic heterocyclic structures onto aryl and heteroaryl bromides using alkyl tosylates in a reductive cross-coupling manifold. This protocol offers an improvement over previous methods by utilizing alkyl tosylate coupling partners that are bench-stable, crystalline solids that can be prepared from inexpensive, commercially available alcohols.

Systematic investigation of alkyl sulfonate initiators for the cationic ring-opening polymerization of 2-oxazolines revealing optimal combinations of monomers and initiators

A systematic kinetic investigation of the living cationic ring-opening polymerization (CROP) involving 2-ethyl-2-oxazoline, 2-methyl-2-oxazoline, and 2-phenyl-2-oxazoline employing a series of alkyl sulfonate initiators with variation of the alkyl initiating fragment (methyl, ethyl, iso-propyl) and the leaving group/counterion (tosylate, nosylate, triflate) is reported. The study reveals that the initiation and propagation reactivity increases in the order tosylate<nosylate<triflate. Slow initiation is observed for EtOTs, while EtONs is a sufficiently fast initiator even for 2-phenyl-2-oxazoline. It is thus recommended to avoid the use of alkyl tosylates, except MeOTs, as initiators for the CROP of 2-alkyl-2-oxazolines. Although triflates are generally the best initiators, the use of the more stable and easier synthesizable nosylates provides a suitable alternative for the design of functional initiators for the CROP of 2-alkyl-2-oxazolines.

Copper-catalyzed reductive cross-coupling of nonactivated alkyl tosylates and mesylates with alkyl and aryl bromides.

A copper-catalyzed reductive cross-coupling reaction of nonactivated alkyl tosylates and mesylates with alkyl and aryl bromides was developed. It provides a practical method for efficient and cost-effective construction of aryl-alkyl and alkyl-alkyl CC bonds with stereocontrol from readily available substrates. When used in an intramolecular fashion, the reaction enables convenient access to various substituted carbo- or heterocycles, such as 2,3-dihydrobenzofuran and benzochromene derivatives.

Iron-catalyzed directed alkylation of aromatic and olefinic carboxamides with primary and secondary alkyl tosylates, mesylates, and halides.

Alkenes, arenes, and heteroarenes possessing an 8-quinolylamide group as the directing group are alkylated with primary and secondary alkyl tosylates, mesylate, and halides in the presence of Fe(acac)3/diphosphine as a catalyst and ArZnBr as a base. The reaction proceeds stereospecifically for alkene substrates and takes place without loss of regiochemical integrity of the starting secondary tosylate, but with loss of the stereochemistry of the chiral center.

One-pot efficient synthesis of disulfides from alkyl halides and alkyl tosylates using thiourea and elemental sulfur without contamination by higher polysulfides

An efficient and odorless synthesis of disulfides from alkyl halides using thiourea and elemental sulfur in the presence of sodium carbonate in wet polyethylene glycol (PEG 200) at 40 °C without contamination by higher polysulfides has been developed. This procedure was then extended to preparation of disulfides from alkyl tosylates at 70 °C.

Palladium-catalyzed borylation of primary alkyl bromides.

A mild Pd-catalyzed process for the borylation of alkyl bromides has been developed using bis(pinacolato)diboron as a boron source. This process accommodates the use of a wide range of functional groups on the alkyl bromide substrate. Primary bromides react with complete selectivity in the presence of a secondary bromide. The generality of this approach is demonstrated by its extension to the use of alkyl iodides and alkyl tosylates, as well as borylation reactions employing bis(neopentyl glycolato)diboron as the boron source.

Palladium-Catalyzed Allylic Cross-Coupling Reactions of Primary and Secondary Homoallylic Electrophiles

The Pd(0)-catalyzed allylic cross-coupling of homoallylic tosylate substrates using boronic acids and pinacol esters is reported. The reaction uses 2-(4,5-dihydro-2-oxazolyl)quinoline (quinox) as a ligand and is performed at ambient temperature. The scope of the reaction is broad in terms of both the boronate transmetalating reagent and the substrate and includes secondary tosylates. Mechanistic studies support an alkene-mediated S(N)2-type stereoinvertive oxidative addition of unactivated primary and secondary alkyl tosylates.

ChemInform Abstract: N‐Heterocyclic Carbene‐Catalyzed Oxidative Esterification Reaction of Aldehydes with Alkyl Halides under Aerobic Conditions.

AbstractAn efficient IMesCl‐catalyzed oxidative esterification of various aromatic and aliphatic aldehydes with alkyl halides and alkyl tosylates is presented.

A convenient, rapid, and general synthesis of α-oxo thiocyanates using clay supported ammonium thiocyanate

A very rapid, convenient, and general method for the synthesis of α-oxo thiocyanates has been described by using clay supported ammonium thiocyanate. The procedure avoids the use of additional catalyst, solvent, aqueous work-up and the yields are high. Moreover, the method is applicable for a variety of aryl, heteroaryl, alkyl α-halo carbonyls, β-keto tosylates, α-halo β-dicarbonyl, α-tosyl, β-dicarbonyl, alkyl halide, and alkyl tosylates.

Uracyl derivatives functionalized with N-, S-, O-heterocycles

Reactions of 1,3-bis(bromopentyl)-5(6)-substituted uracyls with a series of five-membered heterocycles containing in the ring N, S, or O atoms and a mercapto group as a substituent at the carbon atom of the ring afforded uracyl derivatives of acyclic and macrocyclic structure with 2-thiobenzoxazole, 2-thio-5-methyl-1,3,4-thiadiazole, 2-thiobenzimidazole, and 2,5-dithio-1,3,4-thiadiazole fragments. N atoms of benzoxazole and imidazole fragments of compounds obtained undergo alkylation and quaternization with alkyl iodides and alkyl tosylates.

Special features of the alkylation of 7-bromo-5-(2-chlorophenyl)- 3-hydroxy-1,2-dihydro-3h-1,4-benzo- diazepin-2-one with alkyl tosylates

On interacting 7-bromo-5-(2-chlorophenyl)-3-hydroxy-1,2-dihydro-3H-1,4-benzodiazepin-2-one with methyl, hexyl, dodecyl, and cetyl tosylates, 1-alkyl-7-bromo-5-(2-chlorophenyl)-1,2,4,5-tetrahydro-3H-1,4-benzodiazepin-2,3-diones, and 1-alkyl-7-bromo-5-(2-chlorophenyl)-3-hydroxy-1,2-dihydro-3H-1,4-benzodiazepin- 2-ones were obtained. Only the dione was formed in the case of hexyl tosylate. On alkylating with methyl tosylate only the 3-hydroxy derivative was formed. It was shown that at pH 14 the 1-cetyl and 1-dodecyl-3-hydroxy derivatives were completely converted into the corresponding diones. The molecular and crystal structures of the compounds were established by X-ray structural analysis.

A Novel One‐Step Synthesis of Symmetrical Dialkyl Trithiocarbonates in the Presence of Phase‐Transfer Catalysis

AbstractSymmetrical trithiocarbonates were directly obtained, in moderate to excellent isolated yields, by the reaction of various primary, secondary, allylic and benzylic halides or alkyl tosylates with a suspension of granulated KOH and alumina in CS2 under phase‐transfer catalysis. In this manner, cyclic trithiocarbonates such as 1,3‐dithiolane‐2‐thione can also be prepared without formation of any polymeric by‐products.

Synthesis and reactions of enantiomerically pure dialkyl diselenides from the p-menthane group

A convenient route for the synthesis of optically active dialkyl diselenides from the p-menthane system utilizing a reaction of alkyl tosylates and chlorides with sodium diselenide is reported. The diselenides obtained have been used for asymmetric methoxyselenenylation of styrene. Quantum chemical calculations of the chair conformers stability of the terpeneselenenyl bromides from the p-menthane group have also been carried out using density functional theory (DFT, at the B3LYP/6-311G(d) level). The influence of the diselenides structure on the stereoselectivity in the methoxyselenenylation reaction is also discussed.

Chemoselective and Scalable Preparation of Alkyl Tosylates under Solvent‐Free Conditions.

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NaBH4/S8/Wet neutral alumina; as an efficient reagent for facile synthesis of dialkyl disulfides under solvent free conditions

Alkyl halides and tosylates were easily converted to their corresponding symmetrical dialkyl disulfide under solvent free mild reaction conditions using NaBH4/S8/wet neutral alumina in moderate to good isolated yields.

Chemoselective and scalable preparation of alkyl tosylates under solvent-free conditions

The improved method for the efficient tosylation of alcohols has been reported using two procedures (A and B). Procedure A: methanol, ethanol, benzyl alcohols, and valuable ethylene glycols can be converted into their corresponding alkyl tosylates in very fast, simple, and efficient grinding method using potassium carbonate as solid base. Other primary and secondary alcohols need to add potassium hydroxide to reaction mixture (procedure B). High selectivity of tosylation was observed for these two procedures. Scale up ability was found in this method even in 100 mmol of substrate. The present method is the example of solid-state tosylation using tosyl chloride, and is a green chemical process due to solvent-free conditions.

Trisodium heptaphosphide in reactions with alkyl and aryl tosylates

Reactions of trisodium heptaphosphide with alkyl tosylates gave dialkylheptaphosphides or trialkylheptaphosphines, depending on the stoichiometric ratios of the starting reagents. A method for determination of the coupling constants of the asymmetric isomer of trialkyl-heptaphosphines was proposed. Reactions of the heptaphosphide trianion with aryl tosylates yielded disodium hexadecaphosphide.

Syntheses and Reactions of New Optically Active Terpene Dialkyl Diselenides

AbstractThe reaction of sodium diselenide with optically active alkyl tosylates or chlorides is found to be a useful method for the synthesis of optically active dialkyl diselenides. Optically active monoterpene diselenides derived from menthane, carane, pinane, and bornane systems have been obtained. The influence of the terpene fragment of the obtained diselenides on the diastereomeric excess of the methoxyselenylation products has been investigated. The best result for methoxyselenylation was observed for (–)‐diisopinocamphyl diselenide. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2006)

Copper(I) Chloride‐Catalyzed Three‐Component Coupling Reaction of Primary Amines with Electrophiles and α‐Halogen‐Substituted Allylsilanes to Form Unsymmetrical Tertiary Amines

AbstractTertiary amines with three different substituents, in one of which a vinylsilane functionality was included, were straightforwardly formed by the copper(I) chloride‐catalyzed tandem reaction of primary amines, α‐halogen‐substituted allylsilanes, and electrophiles such as electron‐deficient olefins, alkyl halides, alkyl tosylates, or epoxides. In the case using electron‐deficient olefins as the electrophile, the addition of chloroacetone to the reaction system afforded the three‐component coupling reaction more effectively. The addition of trimethyl borate as a co‐catalyst improved the yields of the three‐component coupling products in the reaction using alkyl halides, alkyl tosylates, or epoxides as the electrophiles, although the reaction times were lengthened.