Ethylmagnesium tris

The X-ray crystal-structure determination of ethylmagnesium tris(3-phenylpyrazolyl) hydroborate (232) (Figure 94) shows that the magnesium atom is penta-coordinate as the result of one a-bonded ethyl group, three magnesium-nitrogen bonds with the tris(3-phenylpyrazolyl)hydroborate moiety and one additional, coordinating THF molecule. 

Diesters and even triesters have been converted to bis- and tris(cyclopropanol)s, respectively. Dimethyl succinate gave the bis (cyclopropanol) derivative 17 in 80% yield, while triethyl trans-cyclopropanetricarboxylate (18) yields the tris (cyclopropanol) 19 (90%) (Scheme 11.4 selected examples in Table 11.2) [77,78], Higher homologous dicarboxylic acid diesters are likewise smoothly converted with ethylmagnesium bromide in the presence of Ti(OiPr)4 to provide the corresponding bis (cyclopropanol) s [71,78]. 

Table 11.2. Bis- and tris(cyclopropanol)s from di- and tricarboxylic acid ethyl esters and ethylmagnesium bromide in the presence of titanium tetraisopropoxide.

Ethyl acetoacetate, 2,2,2-Tris(bromomethyl)ethanol, Zinc, 2440 Ethylmagnesium bromide, 0847... 

Diisobutyl(iodomethyl)aluminum, 114 Dimethylaluminum chloride, 5 Ethylaluminum dichloride, 5, 44, 306 Ethylmagnesium bromide-Methyl-aluminum bis(2,4,6-tri-r-butyl-phenoxide), 203 Isobutyl(2,4,6-tributylphenoxy)-aluminum trifluoromethanesulfonate, 113... 

Diethylgold bromide, 1666 Dimethylantimony chloride, 0896 Dimethylbismuth chloride, 0889 Ethylmagnesium iodide, 0855 Methylmagnesium iodide, 0445 Methylzinc iodide, 0446 ALKYLALUMINIUM HALIDES GRIGNARD REAGENTS TRI Al, KYI,ANTIMONY HALIDES... 

Not only lithium-derived organometallic compounds have proved to be suitable reagents for generating a new C —P bond Grignard and cadmium compounds have also found some applications, but they are not so widespread. For example, tris(pentafluorophenyl)phosphane (26) and bromobis(pentafluorophenyl)phosphane (27) both give ethy bis(pentafluoro-phenyl)phosphane (28) on reaction with ethylmagnesium bromide.12... 

Reaction of 142 with trimethylsilyl cyanide and allyltrimethylsilane under SnCl4 catalysis yields the tris(cyanide) 147 and the tris(allyl)tribenzotri-quinacene 148 [98]. Substitution of the bromine atoms takes place very efficiently by treatment of 142,145 and 146 with trimethylaluminum, to give trime-thyltribenzotriquinacene 149 and the tetraalkyl-substituted analogues 150 and 151, respectively, in excellent yields (>90%) [100]. Whereas reaction of 142 with triethylaluminum gives rise to complete reduction to 7, use of ethylmagnesium bromide affords 152 in low (20%) yield. A variety of further carbon-bonded sub-... 

To a solution of ethylmagnesium bromide in 350 ml of THF, prepared from 0.5 mol of ethyl bromide (see Chapter II, Exp. 6) was added in 10 min at 10°C 0.47 mol of 1-hexyne (Exp. 62) and at 0°C 0.47 mol of trinethylsilylacetylene (Exp. 31) or a solution of 0.60 mol of propyne in 70 ml of THF (cooled below -20 C). With tri-methyl si lyl acetylene an exothermic reaction started almost immediately, so that efficient cooling in a bath of dry-ice and acetone was necessary in order to keep the temperature between 10 and 15°C. When the exothermic reaction had subsided, the mixture was warmed to 20 C and was kept at that temperature for 1 h. With 1-hexyne the cooling bath was removed directly after the addition and the temperature was allowed to rise to 40-45°C and was maintained at that level for 1 h. 

It turns out that distillation as a separation technique, is very much the domain of the organic chemist rather than the inorganic. One important exception is the cross-over area of organometallic chemistry for example, many tin-containing compounds, such as tetraethyltin and tri-n-butyltin hydride, are high boiling-temperature liquids, which are separated from the reaction mixture and purified by distillation. Tetraethyltin is prepared by the reaction of tin tetrachloride with ethylmagnesium bromide... 

Ghromium trichloride tri(tetrahydrofuranate) stirred under Ng into tetra-hydrofuran, treated dropwise at —20° with ethylmagnesium bromide in tetra-hydrofuran, the resulting clear triethglchromium soln. treated at —20° with 2-butyne, and allowed to stand 3 days at room temp. hexamethylbenzene. Y 60% based on chromium compound.—These condensations are considered to proceed via acetylenic yr-complexes of chromium and are useful as a general synthetic method. F. e. s. W. Herwig, W. Metlesics, and H. Zeiss, Am. Soc. 81, 6203 (1959) with metal carbonyl compounds, particularly [Go(GO)4]2Hg, s. W. Hiibel and G. Hoogzand, B. 93, 103 (1960). 

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