Boron trifluoride adduct

Table 4. Boron Trifluoride Adducts with Oxygen-Containing Compounds...

Table 5. Boron Trifluoride Adducts with Compounds Containing Chlorine and Fluorine...

The reactions of boron trifluoride adducts of ammonia,and primary, secondary, and tertiary amines with phosphorus pentachloride have been studied and in the first two cases acyclic phosphazenes were obtained. With the ammonia-adduct, a previously characterized phosphazene salt was obtained ... 

Boron trifluoride adducts approximating to K2[Cr04(BF3)2] and K2[Cr04(BF3)3] have been reported.1421... 

DISPROPORTIONATING SALTS A number of salts of weak acids and bases, such as boron trifluoride adduct compounds, dis-... 

In boron trifluoride adducts, fluorine displacement is relatively difficult and, thus, the widest range of adducts has been prepared for the trifluoride (66,120). As fluorine is replaced by successively heavier halogens the displacement of halogen occurs more readily and secondary reactions of the initially formed donor-acceptor adducts... 

Fig. 34. Fe(CO)3[CH2=CH-CH= CH-S(0)0] BF3. (Reprinted, with permission, from Crystallographic Studies on Sulfur Dioxide Insertion Compounds. I. The Butadieneiron Tricarbonyl-Sulfur Dioxide-Boron Trifluoride Adduct, Churchill, M. R., Wormald, J. Inorg. Chem. 9, 2434, Fig. 1, copyright, 1970, by the American Chemical Society)...

Reetz and co-workers determined the structure of the benzaldehyde-boron trifluoride adduct by X-ray crystallography in 1986 (Fig. 1-1) [8J, which shows that the Lewis acid is placed 1.59 A from the carbonyl oxygen, along the direction of the oxygen lone pair and anti to the phenyl substituent. 

Since the boron trifluoride adduct is the most stable adduct of the boron complexes of methylenetriphenylphosphorane 121>, it might be expected that this Lewis acid would also form a stable nitrogen ylid adduct. Treatment of the ylid with boron trifluoride gave a white crystalline solid whose properties were consistent with the proposed adduct 11 °>. The adduct decomposes to trimethylamine trifluoroborane... 

It was observed that the shift of the boron trifluoride adducts were all essentially similar, and no conclusions could be drawn a similar situation was found in our study of ketone-boron trifluoride complexes. 

The novel stannocenophanes (59)-(61) were prepared from reactions of the appropriate disodium (phenylenedimethylene)dicyclopentadienides with tin(II) chloride <84JOM(264)295>. The boron trifluoride adduct of the para compound was also isolated. 

As expected, the compound is highly reactive and readily decomposes. Phosphorus trifluoride reacts with iVN -dimethylethylenediamine to give (58), and a borine adduct is formed by attachment to the phosphorus atom. In the 1 1 boron trifluoride adduct, however, the donor site is nitrogen, but n.m.r. spectroscopy shows the presence of two isomeric forms due to different orientations of the P— F bond. Further BF3 addition leads to reversible formation of (59). Reactions of cyclic and acyclic phosphoramidites... 

Chiroptical Properties. Allinger and Riew have shown that the o.r.d. behaviour of trans-(3R,5R)- — )-3,5-dimethylcyclohexanone and 3,3,5-(R)-trimethylcycIohexanone is not consistent with the Octant Rule in a consideration of the contribution of a P-axial methyl group to the Cotton effect of a cyclohexanone. A c.d. study of cyclo-hexenones has been made and the conformational significance of the data discussed. The magnetic rotary power (Faraday Effect) of some methyl-substituted cyclohexenones and their boron trifluoride adducts have been examined. Conformational equatorial-axial and equatorial-equatorial increments to the magnetooptical rotatory dispersion behaviour of 1,2-, 1,3- and 1,4-dialkyIcyclohexanes have been calculated. The equatorial-axial conformation was found to make a larger re-contribution than equatorial-equatorial form. 

The regioselective functionalization of pyridines using metallation or halogen/metal exchange reactions has been reviewed. There has been a detailed mechanistic study of the ort/io-lithiation of 2-fluoro- and 2,6-difluoro-pyridines by lithium diisopropy-lamide (LDA) in tetrahydrofuran at -78°C where aggregation and aggregate-exchange phenomena are critical.The mono-lithiation of the boron trifluoride adduct of 3-chloro- and 3-bromo-pyridines results in reaction at the 2-position. However, with two equivalents of LDA, the 2,6-dilithiated derivatives may be formed. Subsequent reaction with electrophiles may result in the formation of 2-, 6-, or 2,6-substituted products. " ... 

CgH,nClaNPt, Trichloro(ir-hex-5-enylammonium)platinum(lI), 433, 1037 CyHaFeNOa, Tetracarbonyl(acrylonitrile)iron, 26, 684 27, 824 C7H68F3Fe05S, 3utadieneiron tricarbonyl - sulfur dioxide - boron trifluoride adduct, 353, 516 C7HeFe03, Butadieneiron tricarbonyl (gas-ed), 353, 895 C7HgFe03, Butadienetricarbonyliron, 28, 605... 

First and foremost is the existence of isolable coordination compounds. By analogy with ammonium ions and the boron trifluoride adduct of ammonia (discovered by Gay-Lussac in 1809) it has been possible to isolate and characterize oxonium salts of alcohols, ethers, and ketones (49,176,314) and to prepare Lewis acid adducts of the ethers, sulfides, and phosphines (329), as well as many other compounds which fall under our definition of weak bases. 

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