Methyl aluminum trifluoroacetate

Preferential protonation of oxygen in comparison to carbon prevents 4-methyl-enetetrahydropyran from undergoing reduction to 4-methyltetrahydropyran even when held at 70° for 10 hours in the presence of triethylsilane and a 20-fold excess of trifluoroacetic acid.146 However, when the reaction conditions are changed so that a dichloromethane solution of the same substrate is treated with a mixture of four equivalents of triethylsilane and three equivalents of aluminum chloride in the presence of excess hydrogen chloride, a 40% yield of 4-methyltetrahydropyran product is obtained at room temperature after one hour (Eq. 75).136... 

GABA HMG-CoA HMPA HT LDA LHMDS LTMP NADH NBH NBS NCS NIS NK NMP PMB PPA RaNi Red-Al RNA SEM SnAt TBAF TBDMS TBS Tf TFA TFP THF TIPS TMEDA TMG TMP TMS Tol-BINAP TTF y-aminobutyric acid hydroxymethylglutaryl coenzyme A hexamethylphosphoric triamide hydroxytryptamine (serotonin) lithium diisopropylamide lithium hexamethyldisilazane lithium 2,2,6,6-tetramethylpiperidine reduced nicotinamide adenine dinucleotide l,3-dibromo-5,5-dimethylhydantoin A-bromosuccinimide A-chlorosuccinimide A-iodosuccinimide neurokinin 1 -methyl-2-pyrrolidinone para-methoxybenzyl polyphosphoric acid Raney Nickel sodium bis(2-methoxyethoxy)aluminum hydride ribonucleic acid 2-(trimethylsilyl)ethoxymethyl nucleophilic substitution on an aromatic ring tetrabutylammonium fluoride tert-butyldimcthyisilyl fert-butyldimethylsilyl trifluoromethanesulfonyl (triflyl) trifluoroacetic acid tri-o-furylphosphine tetrahydrofuran triisopropylsilyl A, N,N ,N -tetramethy lethylenediamine tetramethyl guanidine tetramethylpiperidine trimethylsilyl 2,2 -bis(di-p-tolylphosphino)-l,r-binaphthyl tetrathiafulvalene... 

NMO NMP Nu PPA PCC PDC phen Phth PPE PPTS Red-Al SEM Sia2BH TAS TBAF TBDMS TBDMS-C1 TBHP TCE TCNE TES Tf TFA TFAA THF THP TIPBS-C1 TIPS-C1 TMEDA TMS TMS-C1 TMS-CN Tol TosMIC TPP Tr Ts TTFA TTN N-methylmorpholine N-oxide jV-methyl-2-pyrrolidone nucleophile polyphosphoric acid pyridinium chlorochromate pyridinium dichromate 1,10-phenanthroline phthaloyl polyphosphate ester pyridinium p-toluenesulfonate sodium bis(methoxyethoxy)aluminum dihydride (3-trimethylsilylethoxy methyl disiamylborane tris(diethylamino)sulfonium tetra-n-butylammonium fluoride f-butyldimethylsilyl f-butyldimethylsilyl chloride f-butyl hydroperoxide 2,2,2-trichloroethanol tetracyanoethylene triethylsilyl triflyl (trifluoromethanesulfonyl) trifluoroacetic acid trifluoroacetic anhydride tetrahydrofuran tetrahydropyranyl 2,4,6-triisopropylbenzenesulfonyl chloride 1,3-dichloro-1,1,3,3-tetraisopropyldisiloxane tetramethylethylenediamine [ 1,2-bis(dimethylamino)ethane] trimethylsilyl trimethylsilyl chloride trimethylsilyl cyanide tolyl tosylmethyl isocyanide meso-tetraphenylporphyrin trityl (triphenylmethyl) tosyl (p-toluenesulfonyl) thallium trifluoroacetate thallium(III) nitrate... 

Scheme 1. Abbreviations TFAA, trifluoroacetic anhydride DMF, N,N-dimethylformamide 2EHCOC1, 2-ethylhexanoyl chloride LAH, lithium aluminum hydride MeOTf, methyl trifluoromethanesulfonate.

Cyclodehydration Aluminum chloride see also Methyl fluorene-9-carboxylate). Dowtherm. Fluorosulfonic acid. Hydrogen fluoride. Perchloric add. Phosphorus pentoxide. Phosphoryl chloride. Polyphosphate ester. Polyphosphoric add. Potassium bisulfate. Sodium aluminum chloride. Sulfur trioxide-Dimelhylformamide. />-Toluenesulfonic acid. Trifluoroacetic acid. Trifluoroacetic anhydride. 

Oxymercuration of simple alkyl- and acyl-substituted cyclopropenes generally results in ring opening.Addition of mercury(II) acetate to 3-methyl-3-phenylcyclopropene, however, gave a low yield of a cyclopropane containing organomercury compound (15-20%), which was converted into an isomeric mixture of 1 -methoxy-2-methyl-2-phenylcyclopropanes by reduction with lithium aluminum hydride. Reaction of 5 with mercury trifluoroacetate in methanol and then sodium hydroxide led predominantly to one cylopropane. ... 

The following are some further examples. Acetomesitylene is obtained from mesitylene and glacial acetic acid in the presence of phosphoric oxide and kieselguhr, yields reaching 82.5%.525,566 (o-Nitrobenzoyl)mesitylene is obtained (75%) from mesitylene and a-nitrobenzoic acid in the presence of boron trifluoride and trifluoroacetic anhydride.567 Toluene and benzoic acid in the presence of molybdenum pentafluoride give a 70% yield of 4-methylbenzo-phenone, but with aluminum chloride give a mixture of the 2- and the 4-methyl derivative.568... 

After purification of human serum bile acids on an Amberlyst A-26 anion e.xchanger, Sjovall and co-workers (31, 120, 121) hydrolyzed the concentrated bile acids in alkali and extracted the free acids with ethyl acetate. After methylation, the methyl cholanoates were purified on an aluminum oxide column. The bile acid fraction then obtained was subjected to gas-liquid chromatography on CNSi columns after conversion to trifluoroacetate... 

With the procedure of Okishio et al. (24,124) freeze-dried rat liver homogenates are exhaustively extracted with 95% ethanol containing 0.1% ammonium hydroxide, and the extract is taken to dryness. The residue is dissolved in aqueous NaOH, pH 11, and applied to an Amberlyst A-26 anion exchanger. After alkaline or enzymatic hydrolysis the free bile acids are extracted with diethyl ether after acidification. The bile acids are methylated and then purified on aluminum oxide. The bile acid methyl ester fraction eluted from this column is taken to dryness and the residue is trifluoroacet-ylated and analyzed on a triple-component column (QF-1-SE-30-NGS) for quantitative determination. 

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