Ethyl zinc iodide

Edward Frankland (1825-1899) discovered the first transition metal alkyl complexes - diethylzinc ( mobile fluid") and ethyl-zinc iodide ( white mass of crystals ) - while he worked in Robert Bunsen s Marburg laboratory (1849). Frankland was later a professor of chemistry in London. Alkyl-metal bonding occurs in practically all catalytic processes involving hydrocarbons, e. g., hydroformylation (Section 2.1.1), hydrogenation of olefins (Section 2.2), hydrocarbon activation (Section 3.3.6), and C-H-activation (Chapter 4). 

During Frankland s experiment a white crystalline compound was deposited. Investigation of this ethyl zinc iodide led to his systematic study of organometallic compounds. 

Bis-(iodomethyl)zinc-zinc iodide, 108 17 a,20 20,21-Bismethylenedioxy- U,2 -di-hydroxypregn-4-ene-3,11 -dione, 425 17a,20 20,21-Bismethylenedioxy-3,3-ethyl-enedioxy-5a,6a-oxidopregnan-l 1-one and 5 3,6p-oxide, 3... 

The cyclopropanation of 1-trimethylsilyloxycyclohexene in the present procedure is accomplished by reaction with diiodomethane and diethylzinc in ethyl ether." This modification of the usual Simmons-Smith reaction in which diiodomethane and activated zinc are used has the advantage of being homogeneous and is often more effective for the cyclopropanation of olefins such as enol ethers which polymerize readily. However, in the case of trimethylsilyl enol ethers, the heterogeneous procedures with either zinc-copper couple or zinc-silver couple are also successful. Attempts by the checkers to carry out Part B in benzene or toluene at reflux instead of ethyl ether afforded the trimethylsilyl ether of 2-methylenecyclohexanol, evidently owing to zinc iodide-catalyzed isomerization of the initially formed cyclopropyl ether. The preparation of l-trimethylsilyloxybicyclo[4.1.0]heptane by cyclopropanation with diethylzinc and chloroiodomethane in the presence of oxygen has been reported. "... 

Aziridines have been synthesized, albeit in low yield, by copper-catalyzed decomposition of ethyl diazoacetate in the presence of an inline 260). It seems that such a carbenoid cyclopropanation reaction has not been realized with other diazo compounds. The recently described preparation of 1,2,3-trisubstituted aziridines by reaction of phenyldiazomethane with N-alkyl aldimines or ketimines in the presence of zinc iodide 261 > most certainly does not proceed through carbenoid intermediates rather, the metal salt serves to activate the imine to nucleophilic attack from the diazo carbon. Replacement of Znl2 by one of the traditional copper catalysts resulted in formation of imidazoline derivatives via an intermediate azomethine ylide261). 

Ketoester 208 derived from l-(2-nitrophenyl)-lH-pyrrole and ethyl oxalyl chloride can be selectively reduced at the keto group with zinc iodide and sodium cyanoborohydride. Further reduction of the nitro group and cyclization to lactam 209 has been accomplished by treatment with stannous chloride in refluxing ethanol (Scheme 43 (2003BMCL2195)). 

Diethylzinc, one of the first organometallic compounds to be isolated (Fran-kland, 1849), epitomizes these characteristics. The compound is easily prepared by heating powdered zinc or zinc-copper alloy with ethyl iodide under an atmosphere of dry nitrogen or CO2 (the initial product is actually C2H5ZnI, which disproportionates on distillation to zinc iodide and diethylzinc) ... 

Further versatility of this approach has been realized with contrasting Lewis acid promoted additions of silyl ketene acetals, (191) to (194), to ethyl propynoate (Scheme 42). In fact, the tandem 1,4-conjugate addition-electrophile trapping protocol is feasible when titanium(IV) tetrachloride is employed. In situ functionalization of the intermediate titanate enoate (259), with select electrophiles, affords a-substituted enoates (260) to (262). On the other hand, the zinc iodide and zirconium(IV) tetrachloride protocols afford directly -y-alkoxycarbonyl-a-trimethylsilylenoates (263) and [2 + 2] adducts (264), respectively.100... 

Starting olefins. No insertion of methylene group into the C—H bond linked to the olefinic double bond is observed. Thus the mechanism of reaction (8) is closely related to that of the Simmons-Smith reaction. However, reaction (8) is much more rapid than the corresponding Simmons-Smith reaction, and methylene iodide must be added slowly to moderate the reaction. The first step of reaction (8) was shown to be the formation of ethyl iodide and iodomethylethylzinc (XIII), which undergoes methylene transfer reaction with olefins. Since two ethyl-zinc... 

Zinc ethyl iodide is a white crystalline product which decomposes into zinc diethyl and zinc iodide when distilled in a stream of carbon dioxide. The following are some of the reactions carried out with zinc ethyl iodide —... 

By the distillation of ethyl mercuric iodide with zinc diethyl. ... 

Related reagent, ethyUodomethyliinc, QHjZnCHsl.12 Mol. wt. 235.38. The leagcnt is prepared by the reaction of ethyl iodide with zinc-copper couple in ihxoliite ether to give ethylzinc iodide (I). probably in equilibrium with diethyl-llttc and zinc iodide. This stock solution can be stored at room temperature for a... 

Hydroxymethyl-1,4-benzodioxin (137) obtained in 80% yield by reduction of ethyl 1,4-benzo-dioxin-2-carboxylate (39) with lithium aluminum hydride in refluxing ether <91TL5525> reacted with zinc azide bis-pyridine complex under Mitsunobu conditions (triphenylphosphine, diisopropyl azodicarboxylate) to yield exclusively compound (138) in 75% yield. Otherwise, (137) was first reacted with zinc iodide under the same conditions until complete transformation of the starting material into the mixture of regioisomers (139) and (140) excess of dry piperidine was then added to the crude reaction medium to yield the alkenic analogue (141) of Piperoxan <89TL1637>. 

The iodide occurs as its double salt with zinc iodide when phosphorus, ethyl iodide and zinc are heated together at 160° ., or on heating ethyl iodide with a phosphorus-zinc alloy at 180° C. (5) The... 

Tetraethyltin has been prepared from tin-sodium alloy and ethyl iodide, from tin-sodium-zinc alloy and ethyl bromide, and from tin tetrachloride and ethylmagnesium bromide. The method described is essentially that of Pfeiffer and Schnur-mann. ... 

The possibility of a radical mechanism is supported by the observation of the accelerating effect of molecular oxygen on the cyclopropanation. Miyano et al. discovered that the addition of dioxygen accelerated the formation of the zinc carbenoid in the Furukawa procedure [24a, b]. The rate of this process was monitored by changes in the concentration of ethyl iodide, the by-product of reagent formation. Comparison of the reaction rate in the presence of oxygen with that in the... 

Cyclohexene, purification of, 41, 74 reaction with zinc-copper couple and methylene iodide, 41, 73 2-CyclohEXENONE, 40,14 Cydohexylamine, reaction with ethyl formate, 41, 14... 

Contact with RmMX (R is methyl, ethyl M is aluminium, zinc X is bromide, iodide) causes ignition. Diethylaluminium bromide, dimethylaluminium bromide, ethylaluminium bromide iodide, methylzinc iodide and methylaluminium diiodide are claimed as specially effective. 

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