Promoters 1-butyl alcohol

The cyclization of aryl 3-chloropropyl sulfones by potassium t-butoxide in t-butyl alcohol at 30 °C (equation 20) has a p value of 2.32 for substituents in Ar202. This is considered by Bird and Stirling to indicate the formation of an intermediate carbanion which is essentially in equilibrium with the reactants. A recent review by Stirling203 deals with structure-reactivity aspects of many sulfonyl promoted reactions of this type. 

The structure of the substrate also plays an important role. The elimination reaction of compounds [174] in t-butyl alcohol promoted by KOt-Bu at 30°C... 

Water has also been shown to be essential for the liquid phase polymerization of isobutylene with stannic chloride as catalyst (Norrish and Russell, 87). The rates of reaction were measured by a dilatometric method using ethyl chloride as common solvent at —78.5°. With a mixture consisting of 1.15% stannic chloride, 20 % isobutylene, and 78.8% ethyl chloride, the rate of polymerization was directly proportional to the amount of added water (up to 0.43% of which was added). A rapid increase in the rate of polymerization occurred as the stannic chloride concentration was increased from 0.1 to 1.25% with higher concentrations the rate increased only gradually. It was concluded that a soluble hydrate is formed and functions as the active catalyst. The minimum concentration of stannic chloride below which no polymerization occurred was somewhat less than half the percentage of added water. When the concentration of the metal chloride was less than about one-fifth that of the added water, a light solid precipitated formation of this insoluble hydrate which had no catalytic activity probably explains the minimum catalyst concentration. The addition of 0.3% each of ethyl alcohol, butyl alcohol, diethyl ether, or acetone in the presence of 0.18% water reduced the rate to less than one-fifth of its normal value. On the other hand, no polymerization occurred on the addition of 0.3 % of these substances in the absence of added water. The water-promoted reaction was halved when 1- and 2-butene were present in concentrations of 2 and 6%, respectively. 

Samarium(II) iodide promotes comparable transformations of aldehydo sugar 31 to ring contracted product 34 (Scheme 10) [51]. The presences of HMPA and tert-butyl alcohol as a proton source are necessary to obtain good conversion to cyclopentane derivatives. The reac-... 

This alcohol can be reacted with methanol in the presence of a catalyst to produce methyl-r-butyl ether. Although it is currently cheaper to make Ao-butyl alcohol from Ao-butcne (Ao-butylene), it can be synthesized from syngas with alkali-promoted zinc oxide catalysts at temperatures above 400°C (750°F). 

Other methods that have been less regularly used are the dehydration of alcohols with dimethyl sulfoxide to form symmetrical ethers, the photochemical transformation of benzylic chlorides with fert-butyl alcohol, or radical reactions of hcxafluoroacetone with alkanes, Mercury acetate promoted couplings of alcohols with vinyl acetate or vinyl ethyl ether to form vinyl... 

Diphenylcyclopropane has been prepared previously by (1) the Simmons-Smith procedure (24% yleld) b,19 and modified versions of this method (up to 72%),20 (2) sulfonium ylide addition to 1,1-diphenylethene (61% yield),21 (3) reduction of 1,1-diphenyl-2,2-dihalocyclopropanes with sodium in ammonia (47% yield),22 with sodium and tert-butyl alcohol (80%), or with diethyl lithiomethanephosphonate (62%),23 (4) base-promoted cyclization of trimethyl(3,3-diphenylpropyl)ammonium iodide (78%),24 (5) boron trifluorlde-promoted cyclization of a corresponding 3-hydroxypropyistannane (97%),2 (6) reaction of 3,3-diphenylpropenoic acid with lithium aluminum hydride (62%),2 (7) reaction of... 

A further study by Ramirez et al. (1982) also utilized the effect of solvent and ionic state in controlling reactivity patterns. A number of reactions, including the decomposition and nucleophilic substitution processes of p-nitrophenyl phosphate in acetonitrile, were examined. In the absence of added nucleophiles cyclic trimetaphosphate is produced. Both t-butyl alcohol and phenol are phosphorylated under these conditions. A nonaqueous solvent of low polarity should be better than water in promoting the conversion of the highly ionic product to the less polar transition state that would produce metaphosphate. The low steric sensitivity of the reaction and the increased rate of the dianion relative to the monoanion are consistent with either any extended associative transition state or the dissociative transition state. Stereochemical studies of these reactions by Knowles... 

To destroy metallic potassium, the same procedure and precautions as for sodium are used, except that the less reactive t-butyl alcohol is used in the proportion of 21 mL/g of metal. (CAUTION Potassium metal can form explosive peroxides. Metal that has formed a yellow oxide coating from exposure to air should not be cut with a knife, even when wet with a hydrocarbon, because an explosion can be promoted.) If the potassium is dissolving too slowly, a few percent of methanol can be added gradually to the refluxing r-butyl alcohol. Oxide-coated potassium sticks should be put directly into the flask and decomposed with f-butyl alcohol. The decomposition will require considerable time because of the low surface/volume ratio of the metal sticks. 

Sodium ethoxide in ethanol (EtONa/EtOH) and potassium ferf-butoxide in ferf-butyl alcohol (f-BuOK/f-BuOH) are bases typically used to promote E2 reactions. 

Miscellaneous Tricyclic Systems.—The bicyclic ketone (740), available in four steps from the alcohol (739), is converted on irradiation at 310 nm in t-butyl alcohol into the tricyclic alcohol (741), a member of the hitherto unknown tricyclo[2,2,0,0 ]-hexane system.The base-promoted reaction of cyclic a-diketones yields tricyclic... 

How might the ratio of alkenes obtained in the fcrf-butoxide-promoted elimination change if the ferf-butyl alcohol contains water ... 

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