Tetra-„-butylammonium iodide

Reaction of pyrrolopyridines 241 with tosylmethyl isocyanide (TosMIC) in the presence of a phase transfer catalyst tetra- -butylammonium iodide (TBAI) provides the tricyclic pyrimidopyrrolopyrimidine derivatives 242 (Equation 30) <20000L3253, 2004JOC4974, 2005JOC4879>. 

A mixture consisting of the step 2 product (40 g), potassium bicarbonate (48.7 g), tetra-butylammonium iodide (8.0 g), 2,6-di-ter -butyl-4-mcthylphcnol (1.74 g), and 500 ml THF was treated with acrylic acid (11.2 g) and then refluxed for 6.5 hours and stirred at ambient temperature for 16 hours. Thereafter it was diluted with diethyl ether, washed with water, dried, filtered, concentrated, and then dissolved in hot isopropyl alcohol. Upon cooling solids precipitated from the solution and the product isolated after filtering, mp = 50°C. 

The alkylation of 1,2,5-thiadiazepine 112 with benzyl bromide in the presence of sodium carbonate and tetra-butylammonium iodide affords ( )-5-A-benzyl-3-methoxycarbonyl-2-iV-methyl[l,2,5]benzothiadiazepine 1,1-diox-ide 113 in 92% yield (Scheme 25) <2001T7021>. 

The shift of the tetraiodoborate, prepared by the addition of tetra-butylammonium iodide to boron tri-iodide in methylene dichloride solution, varied from +66-0 when the reactants were mixed in 1 1 proportions to +127-5 in the presence of excess of tetrabutylam-monium iodide. Boron tri-iodide in liquid hydrogen iodide at — 43°C has a B shift of +128 p.p.m. 

PHASE-TRANSFER CATALYSTS Adogen 464. (-)-N-Benzyl-N-methylephedrinium bromide. Benzyltriethylamine. Benzyl triethylammonium chloride. 18-Crown-6. Dibenzo-18-crown-6. Diethyl phenylsulfinylmethylphosphonate. Hexadecyltributyl-phosphonium bromide. Methyltricaprylylammonium chloride. Tetra-n-butylammo-nium hydrogen sulfate. Tetra- -butylammonium iodide. 

Tetra- -butylammonium iodide [311-28-4] M 369.4, m 146 . Crystalhse the iodide from toluene/petroleum ether (see entry for the corresponding bromide), acetone, ethyl acetate, EtOH/diethyl ether, nitromethane, aqueous EtOH or water. Dry it at room temperature under a vacuum. It has also been dissolved in MeOH/acetone (1 3, lOml/g), filtered and allowed to stand at room temperature to evaporate to ca half its original volume. Distilled water (Iml/g) is then added, and the precipitate is filtered off and dried. It can also... 

Oxidative Methods.— The oxidation of alcohols to carbonyl compounds using DMSO activated by electrophiles, e.g. oxalyl chloride or trifluoroacetic anhydride, has been reviewed/ DMSO-Metal oxide oxidations of alcohols have been described using molar, or catalytic, amounts of a new oxide of molybdenum/ This yellow oxide, Mo-y , is prepared by hydrogen peroxide oxidation of molybdenum or its trioxide/ N Iodosuccinimide in combination with tetra-butylammonium iodide oxidizes primary and secondary alcohols to aldehydes and ketones in dichloromethane solution/ The corresponding bromo-combina-tion gave inferior yields, and the chloro-combination resulted in polychlorination of the carbonyl product. 

The above section considered anionic cyclization of enediynes and related molecules in a one-pot process, in contrast to the known classical multi-step methods [260, 327-329]. One-step anionic cycloaromatization of enediynes is also an effective method for the synthesis of biarenes [328]. Depending on the reaction conditions and substrate structure, the process can go by two routes. For example, when a methoxide ion attacks the nitrile function of enediyne 3.691, there follows a cascade of cycloaromatization reactions by an anionic pathway, affording phenanthridinones 3.692 in 50% yield after chromatographic purification. On the other hand, reaction of enediyne 3.691 with sodium methoxide in methanol in the presence of two equivalents of tetra-butylammonium iodide at reflux leads to biaryl derivative 3.693 in 56-64% yield. Diynes 3.691 were synthesized in 40-98% yield by the Pd-catalyzed coupling reaction of 2-ethynylbenzonitrile 3.689 with 2-alkynyliodbenzenes 3.690 (Scheme 3.72) [327]. A similar procedure was applied to the cycloaromatization of a series of (Z)-l-aryl-3-decene-l,5-diynes 3.694 to produce biphenyls 3.695 in yields from 14% to 34% (Scheme 3.73) [327]. 

---