109-63-7 boron fluoride etherate

Ethyl acetoacetate reacts with ehaleone in the presence of boron fluoride etherate affording 3-carbethoxy-2-methyl-4,6-diphenylpyryl-ium this can be hydrolyzed and decarboxylated to 2-methyl-4,6-diphenylpyrylium which should theoretically result from acetone and ehaleone. 

In a similar reaction of ketene with diethyl phosphite in the presence of boron fluoride etherate as catalyst, diethyl 1-acetoxyvinylphosphonate is formed [113] see Eq. (69) ... 

The initiation reaction in the polymerization of vinyl ethers by BF3R20 (R20 = various dialkyl ethers and tetrahydrofuran) was shown by Eley to involve an alkyl ion from the dialkyl ether, which therefore acts as a (necessary) co-catalyst [35, 67]. This initiation by an alkyl ion from a BF3-ether complex means that the alkyl vinyl ethers are so much more basic than the mono-olefins, that they can abstract alkylium ions from the boron fluoride etherate. This difference in basicity is also illustrated by the observations that triethoxonium fluoroborate, Et30+BF4", will not polymerise isobutene [68] but polymerises w-butyl vinyl ether instantaneously [69]. It was also shown [67] that in an extremely dry system boron fluoride will not catalyse the polymerization of alkyl vinyl ethers in hydrocarbons thus, an earlier suggestion that an alkyl vinyl ether might act as its own co-catalyst [30] was shown to be invalid, at least under these conditions. 

According to the Keele theory the incorporation of styrene would be represented by Reaction (E). Since Yamashita s experiments were done with the catalyst boron fluoride etherate, whose mode of action is still quite obscure, we denote the activating group derived from the catalyst by Y (which may be Et). 

Additional acylation studies were also reported (24), (26). In the first case it is claimed that acylation of thiophene is achieved by means of HC104 and acetic anhydride affording a 65 % yield of 2-acetylthiophene. In the second paper Levine and coworkers reported that while 2,5-dimethylthiophene could be readily acetylated, 2,5-dichlorothiophene acetylated sluggishly. This is, however, readily explained, since the presence of chlorine atoms on the thiophene ring decreased its reactivity in electrophilic substitution reactions. In the case of methyl substitution, however, the 3 and 4 positions of the ring are activated toward electrophilic substitution by the inductive and hyperconjugative effects. Thus 2,5-dimethylthiophene was successfully acylated by the boron fluoride etherate method in high yield with three aliphatic anhydrides. 

Goldsmith DJ (1962) Cyclization of epoxy olefins reaction of geraniolene monoepoxide with boron fluoride etherate. J Am Chem Soc 84 3913-3918... 

Synonyms boron fluoride etherate boron fluoride ethyl ether... 

The behavior of 2-anhydrous conditions has also been examined in some detail.4 From thiB reaction a crystalline boron fluoride complex was obtained which was spectroscopically characterised as that of the ritf-isomer (XXVII) of A-fert-butylbenzaldoxime. On standing or recrystaUisation from solvent this isomer was converted to the [Pg.326]

The checkers obtained boron fluoride etherate and epichloro-hydrin from Eastman Organic Chemicals and redistilled each through a 23-cm. Vigreux column immediately before use. 

It is convenient to measure the liquids with syringes using the densities epichlorohydrin df 1.179 boron fluoride etherate, < f 1.125. 

The procedure used is essentially that described by Meerwein and co-workers. 2, s The salt also has been prepared from ethyl fluoride and boron fluoride etherate, and from silver fluoborate, ethyl bromide, and ether.4... 

An important general method for preparing indoles involves the catalytic elimination of ammonia from phenylhydrazones of carbonyl compounds having an a-roethylene group. Catalysts include zinc chloride, cuprous chloride, boron fluoride etherate, dilute sulfuric acid, alcoholic hydrochloric acid, and glacial acetic acid. ... 

The authors of this paper proposed an initiation step consisting of the direct attack of boron fluoride etherate onto the monomer ... 

Note that acetic acid is eliminated during the reaction. What effect would sodium acetate have How might boron fluoride etherate or sulfuric acid affect the nucleophilic attack of the phenolic oxygen on acetic anhydride With what might the base, pyridine, associate ... 

The catalytic activity of hydrogen chloride was found by Tarbell and Kincaid 34g). Continuing this work, Tarbell et al. 36) showed that certain acids and bases affect the yields of urethanes obtained from a-naphthyl isocyanate and phenols. Thus, catalytic effects were observed with sodium carbonate and acetate, pyridine, triethylamine, acetic acid, trichloroacetic acid, zinc chloride, hydrogen chloride, and boron fluoride etherate. The latter catalyst and triethylamine were found to be the most effective acidic and basic catalysts, respectively. 

Tosic acid has been used similarly for the preparation of ethylenethioketals. It is a milder catalyst than boron fluoride etherate for condensation of a ketone with ethanedithiol and has been used, in acetic acid solution, for selective conversions, for example of A -androstene-3,ll,17-trione (0.60 g.) into the 3-ethyleneketal (0.40g.). ... 

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