The electrophilic cyanation of alkynyl halides (bromides or chlorides) with N-cyano-N-phenyl-p-methylbenzenesulfonamide (NCTS) using a zinc reagent

A mild procedure has been developed for the O-alkyl­ation of 2-hydroxynaphthoquinones by using phase-transfer catalysts. Optimal yields were obtained when 18-crown-6 (10 mol%) and tetrabutylammonium iodide (10 mol% ) were used as cocatalysts in refluxing tetrahydrofuran containing potassium carbonate. Variability in the product yields (0–82%) was attributed to differences in the reactivity of the alkylating agent and to resonance stabilization of the 2-hydroxynaphthoquinone anion. Comparisons of the UV–visible spectra suggest that the degree of electron delocalization has a marked effect on the outcome of the reaction. Quinoid π-electrons were more delocalized in the absence of a stabilizing counteraction, resulting in lower yields. In the presence of tetrabutylammonium iodide, reduced levels of electron delocalization were detected, possibly as a result of ion pairing between the tetrabutylammonium cation and the C-2 oxygen anion. Enhanced reactivity correlates to a lower level of delocalization, and a combination of both catalysts is necessary to facilitate the O-alkylation.

Some tert-butylcalix[4]arene derivatives were synthesized by thermal and microwave methods. The microwave method was conducted in two ways: (1) all the reactants were added in one batch and (2) the reactants were added in two batches under different conditions. Tetrabutylammonium iodide (TBAI) was used in both methods, and its effect on the reaction rate was studied. In general, the duration of the microwave-assisted reactions in the presence of TBAI, especially in the two-batch method, was shorter, and the yields were higher, than in the thermal reaction. The highest yield of (S)-glycidyl calixarene derivative by the thermal method was obtained by using K2CO3 as a base with MeCN as a solvent in the presence of TBAI, while the lowest yield of the same compound was observed when using acetone in the absence of TBAI. All the synthesized calix[4]arene derivatives were characterized by 1H and 13C NMR experiments.

An efficient azidation of 1,3‐dicarbonyl compounds led to tertiary azides in the presence of tetrabutylammonium iodide (TBAI). TBAI is used as a pre‐catalyst along with aq. tert‐butyl hydroperoxide (TBHP) as an oxidant in aqueous medium. This operationally simple, practical, mild and green method provides an opportunity to synthesize a variety of azidated β‐keto esters, amides, and ketones in good yields.

In this work we have achieved epoxide to cyclic carbonate conversion using a metal-free polymeric catalyst under ambient CO2 pressure (1.02 atm) using a balloon setup. The triazine containing polymer (CYA-ANIS) was prepared from cyanuric chloride (CYA-Cl) and o-dianisidine (ANIS) in anhydrous DMF as solvent by refluxing under the N2 gas environment. The presence of triazine and amine functional groups in the polymer results in the adsorption of CO2 up to 7 cc/g at 273 K. This inspired us to utilize the polymer for the conversion of a series of functionalised epoxides into their corresponding cyclic carbonates in the presence of tetrabutyl ammonium iodide (TBAI) as co-catalyst. The product has wide range of applications like solvent in lithium ion battery, precursor for polycarbonate, etc. The catalyst was efficient for the conversion of different mono and di-epoxides into their corresponding cyclic carbonates under atmospheric pressure in the presence of TBAI as co-catalyst. The study indicates that epoxide attached with electron withdrawing groups (like, CH2 Cl, glycidyl ether, etc.) displayed better conversion compared to simple alkane chain attached epoxides. This is mainly due to the stabilization of electron rich intermediates produced during the reaction (e. g. epoxide ring opening or CO2 incorporation into the halo-alkoxide anion). This catalyst mixture was capable to maintain its reactivity up to five cycles without losing its activity. Post catalytic characterization clearly supports the heterogeneous and recyclable nature of the catalyst.

An efficient O-alkylation of alcoholic tosylates with amines in a K2CO3/CO2 system in the presence of tetrabutyl ammonium iodide (TBAI) provides exclusive formation of carbamates. *CDRI-Communication no: 6143.

An efficient O-alkylation of alcoholic tosylates with amines in a K2CO3/CO2 system in the presence of tetrabutyl ammonium iodide (TBAI) provides exclusive formation of carbamates. *CDRI-Communication no: 6143.

A tunable and practical synthesis of electrophilic sulfenylating reagents, thiosulfonates and disulfides, from inexpensive and easily available sulfonyl chlorides, has been developed. By appropriate choice of solvents, the reaction of sulfonyl chlorides and tetrabutylammonium iodide gave the target products in good to excellent yields, respectively. These transformations probably proceed through a reducing–coupling pathway.magnified image

The novel method for the synthesis of gem-bisarylthio enamines and α-phenylthio ketones was developed via the coupling of α-substituted vinyl azides with thiols in the presence of tetrabutylammonium iodide (TBAI) as a redox catalyst and electrolyte at room temperature. Electronic properties were crucial in the generated products. This protocol features metal- and oxidant-free materials, broad tolerance of substrates, and mild reaction conditions.

Nickel based metal-organic framework as catalyst for chemical fixation of CO2 in oxazolidinone synthesis

Treatment of ortho-amino-substituted aryldiyne derivatives with sulfonyl hydrazides in the presence of tetrabutylammonium iodide (TBAI) and tert-butyl hydroperoxide (TBHP) led to a cascade cyclization reaction to yield sulfonylated indeno[1,2-c]quinolines in moderate to good yields. The features of the methodology include metal-free reaction, the ease of reagent handling, and a broad functional group tolerance.

Protodemetallation of (Z)‐1‐aryl‐2‐germyl‐1‐stannylethenes using hydrochloric acid in the presence of tetraethylammonium chloride (TEACl) proceeds at 0 °C with retention of configuration to afford trans‐1‐aryl‐2‐germylethenes with high yields. In contrast, the reaction using hydroiodic acid in the presence of tetrabutylammonium iodide (TBAI) brings about a novel 1,2‐germyl migration accompanying the destannylation to form 1‐aryl‐1‐germylethenes. These 1,2‐germyl migration products result with especially high selectivity from adducts bearing a substituent at the ortho‐ or para‐position on the aromatic ring in the adduct. However, the germyl(stannyl)ethenes bearing a substituent at the meta position on the ring produce a regioisomeric mixture of a trans‐germylethene and a 1‐aryl‐1‐germylethene. Copyright © 2005 John Wiley & Sons, Ltd.

Cycloaddition of CO2 to challenging N-tosyl aziridines using a halogen-free niobium complex: Catalytic activity and mechanistic insights

Efficient solvent-free fixation of CO2 into cyclic carbonates catalyzed by Bi(III) porphyrin/TBAI at atmospheric pressure

-Pro dipeptide analogues 2 and 3 as shown in Scheme1. The treatment of two diastereomeric mixture (1:1) of N-(α-bromo-α-phenylacetyl)-(L)-proline methyl ester 1 withan amine nucleophile (diphenylmethylamine or dibenzyl-amine) in the presence of tetrabutylammonium iodide (TBAI)and diisopropylethylamine (DIEA) in CH

Aryl and alkyl isocyanates have been efficiently converted into symmetrical trisubstituted aryl and alkyl isocyanurates, catalyzed by sodium p-toluenesulfinate on its own or in the presence of tetrabutylammonium iodide (TBAI), in a solvent-free condition. The latter has been shown to have a higher catalytic activity.