Potassium terf-butoxide

The submitters employed alcohol-free potassium ferf-butoxide, purchased from K K Laboratories, without further purification the checkers employed comparable material taken from a freshly opened bottle purchased from MSA Research Corporation. The submitters report that among approximately ten different bottles of commercial potassium terf-butoxide used, only material from one bottle failed to form the tricarbonate in this procedure. The defective material in this one bottle was an extremely fine powder that failed to dissolve when... 

Potassium terf-butoxide (potassium 2-methyl-2-propanolate)... 

Stabilization by a Nonadjacent n Bond. In contrast to the situation with carbocations (see pp. 408-411), there have been fewer reports of carbanions stabilized by interaction with a nonadjacent 7t bond. One that may be mentioned is 13, formed when optically active camphenilone (11) was treated with a strong base (potassium terf-butoxide). ° That 13 was truly formed was shown by the following facts (1) A proton was abstracted ordinary... 

In a parallel study [100], it was shown that formamide, primary and secondary amines react with esters in the presence of potassium terf-butoxide under the action of microwave irradiation. Substituted amides are formed in yields (generally more than 70%) much higher than under the action of conventional heating (Eq. (48) and Tab. 3.22). 

Yoshimura and coworkers113 anticipated the formation of a compound of this constitution from an elimination of methyl (methyl 2,3,5-tri-O-methyl-a-D-glucofuranosid)uronate employing potassium terf-butoxide. However, the n.m.r. data reported are not consistent146,147 with this constitution. 

The LIC-KOR reagent consisting of stoichiometrically equal amounts of butyllithium ( LIC ) and potassium feri-butoxide ( KOR ) was conceived in Heidelberg and optimized in a trial-and-error effort . The fundamental idea was simple. To activate butyllithium optimally by deaggregation and carbon-metal bond polarization, a ligand was required that would surpass as an electron donor any crown ether but not suffer from the drawback of the latter, i.e. its proneness to /3-elimination. Whereas pinacolates and other v/c-diolates proved too labile to be generally useful, potassium terf-butoxide or any other bulky, hence relatively soluble, potassium or cesium alkoxide was found to serve the purpose. ... 

The preparatively useful and simple N-alkylation procedure that utilizes a combination of carboxylic acid and sodium borohydride has been applied to carbazole giving an efficient 9-ethylation. Also of preparative importance is the use of thallous ethoxide as base in dimethylformamide-ether 9-methyl-, 9-ethyl-, n-propyl-, n-butyl-, benzyl-, and n-allylcarbazoles were efficiently produced, as well as 9,9 -dicarbazolylalkanes using C3, C4, and Cg dihalides. 2-Acetyl- and 2-vinylcarbazole were also efficiently 9-ethylated by this route. Another more recent approach to N-alkylation of carbazole utilizes potassium terf-butoxide in the presence of a catalytic quantity of 18-crown-6 9-methylcarbazole was prepared in high yield. ... 

On the other hand, Wyeth-Ayerst chemists ° encountered limitations with this methodology during their syntheses of spirocyclic 2,4-oxazolidinediones derived from isoindole (Scheme 6.55). For example, reaction of 246 with chlorosulfonyl isocyanate followed by cyclization with potassium terf-butoxide afforded poor to modest yields of 247 when R was a substituted benzyl group. Cyclization of 246 using ethyl chloroformate (ECF), triethylamine and 4-(dimethylamino)pyridine (DMAP) in refluxing tetrahydrofuran (THF) gave 247 in only 29% yield when R was methyl and failed completely if R was an isopropyl group. However,... 

It is apparent from Table IV that with nitrobenzene as the oxidation catalyst the ionization-limited rate was not reached even at a nitrobenzene concentration of 2.7M (0.02M fluorene, 0.02M potassium terf-butoxide). The rate of oxidation at the low nitrobenzene concentrations is first-order in nitrobenzene, fluorene, and base. This is consistent with an oxidation rate determined by Reaction 12 and involving an equilibrium concentration of the fluorene anions. 

The stoichiometry of the oxidation appears to require the formation of potassium superoxide as one of the oxidation products, particularly at long reaction periods and high base concentrations. An oxidation of 3.00 mmoles of benzhydrol (0.12M) in the presence of 9.9 mmoles of potassium terf-butoxide (0.37M) in DMSO (80% )-ter -butyl alcohol (20%) absorbed 4.95 mmoles of oxygen in 27.7 minutes at 25°C. and yielded 2.2 mmoles of the benzophenone-DMSO adduct and 0.8 mmole of benzophenone. A precipitate formed (0.307 gram) which analyzed (23) as 103% (4.25 mmoles) potassium superoxide (K02). 

The effect of the concentration of base requires that the formation of superoxide from peroxide is more rapid and occurs to a greater extent at the higher base concentrations. This conclusion is difficult to test, because both potassium peroxide and potassium superoxide are insoluble in the oxidation solvent and potassium superoxide precipitates from solution with as much as 35% by weight of potassium terf-butoxide or potassium hydroxide (which can be removed by extraction with tert-butyl... 

The oxidations involving lithium ferf-butoxide reach completion (3 minutes for fluorenol, 12 minutes for xanthenol) much sooner than the corresponding reactions utilizing potassium terf-butoxide as base (35 minutes for fluorenol, 27 minutes for xanthenol). This behavior obviously involves Reaction 20 since the initial rates of oxidation were all approximately the same for the lithium- and potassium ferf-butoxide-catalyzed reactions. 

Both Russell (5) and Barton (I) have examined the oxidation of dihydroanthracene in a solvent system consisting of 80% dimethyl sulfoxide and 20% tert-butyl alcohol and with potassium terf-butoxide as the base. In both studies, a large excess of base was used, so that there is a possibility of dicarbanion formation. In the present investigation, only catalytic amounts of base were used, which makes it unlikely that a... 

Adduct 110 has been obtained by decomposition of 1-ethoxycarbonyl-1,4-dihydropyridine with potassium terf-butoxide. It is the ti-adduct that would be expected to form by attack of the hydride ion on the 4-position of pyridine. H- and l3C-NMR studies suggest that 110 is planar and devoid of any homoaromatic character.155 The 13C chemical shifts [6 (in DMSO) 127.9... 

In l-chloro-2-fluoroacenaphthene [5S] and in 2,3-dihalo-2,3-dihydrobenzofiiran [59, 60], potassium terf-butoxide eliminates hydrogen fluoride in preference to hydrogen chloride. trhydrogen fluoride quantitatively on treatment with sodamide in fert-butyl alcohol [60] (equation 29). 

Figure 4 (A to C) shows changes in the ESR spectra obtained with D-mannose phenylhydrazone treated with 1% potassium terf-butoxide in methyl sulfoxide. The original three-line pattern (spectrum A), ascribed to the nitroxide radical, rearranges to a new pattern in about 15 minutes (spectrum B) this pattern remains steady for hours if the solution is kept in the absence of oxygen (spectrum C).

The solutions were examined in a Varian model V-4548 aqueous solution sample cell. All experiments in solution required a trace of oxygen. Freshly prepared solutions of phenylhydrazones or osazones (0.1 to 3.5 mM) in methyl sulfoxide were mixed with base [1 to 3% (90 mM to 270 mM) potassium terf-butoxide in methyl sulfoxide] and exposed to air for about 30 sec. Initial ESR spectra were recorded in about 30 sec after mixing. 

Exercise 17-43 Write a mechanism analogous to that for the Cannizzaro reaction for the benzilic acid transformation. What product would you expect to be formed from diphenylethanedione with potassium terf-butoxide in ferf-butyl alcohol Would you expect a benzilic acid-type rearrangement to occur with 2,3-butanedione Give your reasoning. 

Aryl)thioindoxyls undergo both C- (in the 2-position) and O-alkylation in the presence of potassium terf-butoxide.609 The C-alkylated products (237) react with A-methylpiperidine-4-magnesium chloride to give compounds (238) (as mixtures of a- and /3-racemates), which lose water on treatment with hydrogen bromide to give 239. 

A suspension of potassium terf-butoxide is prepared by a slight modification of the procedure of Johnson and Schneider,2 particular attention being paid to the precautions they recommend for safe handling of potassium. Dry iert-butyl alcohol (1250 ml.) is distilled directly into the reaction flask under nitrogen. One hundred grams (2.6 g. atoms) of potassium cut into about ten pieces is added. The stirred mixture spontaneously warms to the melting... 

Bromination of 8 followed by dehydrobromination afforded completely unsaturated compound 10. Barium hydroxide and zinc reduction of 10 yielded 11 (69JOC3237). ( >1,2-Diazacyclooctene 12 (R1 - R4 = Me) was synthesized by oxidative cyclization of 2,7-dimethyl-2,7-octanediamine with iodine pentafluoride (78CB596). [For preparation of the stereoi-someric Z compounds, see Section II,A,3,a.] Stetterand Koch reacted bis(Af-bromoamino)biadamantyl 13 with potassium terf-butoxide and isolated a molecule containing a 1,2-diazocine sandwiched between two ada-mantane moieties (14) [see also Section II,A,3,c] (75LA1357). 

In addition to pyrolysis or photolysis, S,C cleavage may be induced by nucleophiles (or bases) in substrates with an electrophilic (or acidic) center and a leaving group next to the sulfur1. This is exemplified in the treatment of a bridged thiocyanate with potassium terf-butoxide leading to an a-oxo thioketone which spontaneously dimerizes (equation 58)324. 

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