Diethyl ether, as solvent

The present method offers several advantages over earlier methods. The use of carbon tetrachloride instead of diethyl ether as solvent avoids the intrusion of certain radical-chain reactions with solvent which are observed with bromine and to a lesser degree with chlorine. In addition, the potassium bromide has a reduced solubility in carbon tetrachloride compared to diethyl ether, thus providing additional driving force for the reaction and ease of purification of product. The selection of bro-... 

Using diethyl ether as solvent, SAMP/RAMP-hydrazones of acyclic ketones are alkylated in good chemical yield and generally enantiomeric purities of > 90 % are achieved (see Table 3). Most prominent is the preparation of the alarm pheromone of the ant, ( + )-(5T)-4-methyl-3-hep-tanone, which proceeds with practically complete asymmetric induction5,38. Lower enantiomeric excesses (10-30%) are obtained in the alkylation of ketones which contain a phenyl substituent at the alkylated carbon3,8. 

Iron(II) bis(acetylacetonate) has been prepared by reaction of iron(II) sulfate in aqueous solution with 2,4-pentanedione in the presence of bases such as pyridine and ammonia1 and by reaction of iron (II) chloride tetrahydrate in aqueous solution with the stoichiometric amounts of 2,4-pentanedione and piperidine.2 Neither publication reports yields and the lack of complete experimental details makes duplication difficult. The following procedure is a modification of that reported by Buckingham et al.2 and employs either anhydrous iron(II) chloride or the corresponding adduct with THF. The reaction is carried out in diethyl ether as solvent instead of water. 

Silver nitrite sometimes is used in preference to sodium nitrite, usually in diethyl ether as solvent ... 

Functional l,3-dioxa-2,4,7-trisilacycloheptanes 192 were prepared by the reaction of corresponding silane diols 191 with methyldichlorosilane in the presence of pyridine, as an HC1 acceptor, and diethyl ether, as solvent (Scheme 35). The subsequent reaction of 192 (R1 = Me, Rz = OSi(Me)3) with chlorine in the presence of pyridine afforded chlorosilane 193, which upon treatment with an alcohol gave alkoxide 194. Siloxanes 192-194 were characterized by H, 13C, and 29Si NMR spectroscopic data C1995JOM29, 1996KGS1590>. 

With diethyl ether as solvent, the reaction proceeds with the selective reduction of the tosyl group to give 1-bromo-n-undecane, whereas in diethylene glycol dimethyl ether ( digl5Tne ), the bromo substituent is selectively reduced to yield n-undecyl tosylate. In diethyl ether, the lithium cation is poorly solvated and LiAlIEt reacts as an ion pair. In... 

Treatment of certain 1,3-diketones with sulfur tetrafluoride using diethyl ether as solvent leads to the formation of unsaturated /l-fluoro ketones and mixtures of E- and Z-isomers are obtained,... 

Treatment of certain 1,3-diketones with sulfur tetrafluoride using diethyl ether as solvent leads to the formation of unsaturated /i-fluoro ketones and mixtures of E- and Z-isomers are obtained, e.g. I.8 In this case the monoenolic form of the 1,3-diketone is the substrate for sulfur tetrafluoride. When diethyl ether is not used, the expected conversion of one or two carbonyl groups into difluoromethylene groups occurs. 

Consider the transformation shown below. When CH2C12 is the solvent, formation of 7 occurs exclusively. Use of toluene or diethyl ether as solvent results in a mixture of 7 and 8, with 7 usually predominating. The investigators postulated a mechanism for S02 insertion that was different than the SE2 pathway discussed in Chapter 8.10S... 

Reactions have been carried out using less alkene and diethyl ether as solvent.This generally lowers the yield of the cyclopropane (see table below). 

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