Diethylzinc: Zinc, diethyl

Diethyl phosphite Phosphonic acid, diethyl ester (762-04-9), 75, 22 Diethyl sulfate Sulfuric acid, diethyl ester (64-67-5), 77, 153 Diethyl tartrate, 76, 93 Diethylzinc Zinc, diethyl- (557-20-0), 76, 89... 

Diethylzinc Zinc Diethyl Ethyl Zinc Zinc Ethyl ... 

DIETHYLZINC Zinc Diethyl, Ethyl Zinc, Zinc Ethyl naaiiuMeLl.uM,l 3 3 w... 

Vyac Vinyl Acetate Zinc Diethyl Diethylzinc... 

Diethylzinc — (1) Chemical Designations — Synonyms Zinc Diethyl Ethyl Zinc Zinc Ethyl Chemical Formula (CjHjjjZn (ii) Observable Characteristics — Physical... 

Asymmetric epoxidation of a,jS-unsaturated ketones represents an efficient method for the preparation of optically active a,jS-epoxy ketonesJ Recently, a new and very efficient catalytic system for enantioselective epoxidation of ( )-a,jS-enones to the corresponding trans-epoxy ketones has been developed based on a BlNOL-zinc complexJ Very high yields and excellent diastereo- and enantioselectivities are achieved at room temperature using cumene hydroperoxide (CMHP) as the terminal oxidant and performing the reaction in diethyl ether. A combination of enantio-merically pure BINOL and diethylzinc readily affords the active catalyst in situ (Figure 6.13). ... 

As regards the dimethylcadmium-(7 )-(—)-3,3-diethyl-1,2-butanediol (1 1) catalyst, it was characterised by a lower stereoelectivity than the diethylzinc-(R)-(—)-3,3-dimethyl- 1,2-butanediol (1 1) catalyst in enantioasymmetric polymerisations of propylene sulphide, cA-2-butene sulphide and cyclohexene sulphide, but the elected chirality was opposite to that found for polymers obtained with the zinc-based catalyst [159]. 

According to Jenkins diethylzinc has no effect on molar mass [157]. In contrast to the negative result published by Jenkins there are reports from two other sources on the successful use of diethyl zinc [180-182,466,467]. These differences are either due to different catalyst systems or are due to differences in the addition order of catalyst components. Strong evidence in favor of molar mass control by diethyl zinc was provided by Lynch who used NdV/MgR2-based catalyst systems [466,467]. In combination with NdV/DIBAH/EASC the use of ZnEt2 also resulted in a reduction of molar mass [ 180-182]. A careful study revealed that the formal number of polymer chains (pexp) formed per Nd atom increases with increasing nznEt2/ Ndv-ratios (Table 24). 

The diethylzinc-a-titanium trichloride system gives low molecular weight polymers of diene hydrocarbons 253, 523). Diethyl-zinc and titanium tetrachloride polymerizes alkynes 535). 

A comparative study of the regioselectivities of monocyclopropanation of limonene and 4-vinylcyclohexene in systems using acetyl chloride promoted diiodomethane with zinc dust and copper(I) chloride in diethyl ether, with diethylzinc in toluene and with triethylaluminum in toluene/dichloromethane showed that the procedure using diethylzinc in toluene exhibited the least steric hindrance toward cyclopropanation at more highly substituted, electron-rich double bonds. ... 

Normally the chiral auxiliaries are introduced and removed in the asymmetric synthesis of Simmons-Smith reactions of allylic alcohols to provide mostly /rani-disubstituted cyclopropanes. Stereoselective syntheses of c -disubstituted cyclopropanes are difficult to achieve. Starting from (Z)-3-phenylprop-2-en-l-ol (80a) and (Z)-6-phenylhex-2-en-l-ol (80b), the corresponding c -disubstituted cyclopropanes 81a and 81b were prepared by first treating them with diethylzinc followed by diethyl (- -)-(/ ,7 )-tartrate (DET). A zinc-bridged intermediate is assumed to be formed first. This is subsequently treated with diethylzine and diiodomethane to give the products 81. The reaction conducted at — 12 "C gave the cyclopropanated products 81a and 81b with 70 and 81% ee, respectively.This method has the advantages that the introduction of the chiral auxiliary to the substrate and its removal are not neccessary and that both cis- and trans-disubstituted cyclopropanes could be prepared from (Z)- and ( )-allylic alcohols, repectively. 

After much testing, chemists developed a compound that stabilizes paper diethyl-zinc [Zn(C2H5)2]. Diethylzinc is volatile so it can be sprayed onto books. It reacts with water to form zinc oxide (ZnO) and gaseous ethane (C2Hg). (a) Write an equation for this reaction, (b) ZnO is an amphoteric oxide. What is its reaction with H+ ions ... 

An alternative preparative method avoids the use of the Zn/Cu couple, using diethyl zinc instead. An example is taken from Abad s synthetic studies directed at spongiane.329 in this work, tricyclic alkene 416 was treated with diethylzinc and diiodomethane to give a 91% yield of 417. 

Among the earliest reports of such specialist s tricks to promote a smooth procedure in which an organo halide and a metal were involved, was Pebal s publication on the preparation of diethylzinc in 1861 [1] (see Sect. 1.2.2, p. 3). For the reaction of iodoethane with zinc in diethyl ether he used zinc that had first been etched ( angeatz") with sulfuric acid, washed and carefully dried. 

The effect of a halide upon the cyclopropanation of cyclohexene by diethyl-zinc-di-iodomethane has been reported. Although good yields of norcarane are obtained in the absence of lithium or magnesium halides, in their presence the yield of norcarane deteriorates and there is an increase in the yield of propyl and butyl iodides. Other dihalogeno-compounds besides di-iodo-methane may be used with diethylzinc and, in the case of chloroiodomethane. 

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