Grignard structure

Since only two of the four possible addition products (9) were formed, one may surmise that SKT was not responsible for the low selectivity. The minor isomer was the I (thieo) addition product. The reasons lor the loss of selectivity arc not known, but undoubtedly involve very subtle differences in Grignard structure, possibly caused by the lithium cnrboxylaic and the two mellioxy substituents, although neither of these components on their own caused a loss of selectivity U f. Table 5.2, entry 2 and Table 5.3, entry I). 

R=Et or Ph are found. Unpublished polarographic data in dimethoxy-ethane by Dessy and Psarras also support such a Schlenk equilibrium with for / = Ph or i-Pr. Thus in basic solvents there is definitely a contribution to the Grignard structure by RMgX species. 

Write the structure of the Grignard reagent formed from each... 

Write an equation showing how you could prepare ethyl phenyl ketone from propanenitrile and a Grignard reagent What is the structure of the imine intermediate ... 

The reaction proceeds by formation of the Grignard reagent from o bromofluorobenzene Because the order of reactivity of magnesium with aryl halides is Arl > ArBr > ArCl > ArF the Gngnard reagent has the structure shown and forms benzyne by loss of the salt FMgBr... 

The reaction of quinolinium and isoquinolinium salts with dialkyl cadmium has been observed to be slow and occurs in relatively poor yield. The structures of the products are the same as those obtained from reactior with Grignard reagents and the yields ranged from 0-20% (40). Leadini references to other observed reactions of quinolinium and isoquinoliniuir salts with Grignard reagents can be found in the above cited review (31). 

The stereochemical course of reduction of imonium salts by Grignard reagents was found to depend on the structure of the reagent 714). Hydro-boration of enamines and oxidation with hydrogen peroxide led to amino-alcohols (7/5). While aluminum hydrogen dichloride reacted with enamines to yield mostly saturated amines and some olefins on hydrolysis, aluminum hydride gave predominantly the unsaturated products 716). 

Some structural aspects of the organometallic compounds of the alkali metals have already been briefly mentioned in Section 4.3.6. The diagonal relation of Li with Mg (p. 76), coupled with the known synthetic utility of Grignard reagents (pp. 132-5), suggests that Li, and perhaps the other alkali metals, might afford synthetically... 

What effect does the solvent have on the structure, charges and reactivity of Grignards Compare geometries, atomic charges and electrostatic potential maps of the diethyl ether complex to that of methylmagnesium chloride itself. How does solvent-magnesium bond formation affect the reactivity of the methyl group Explain. 

The early literature on the reactions of the indole Grignard reagents with the simple diacid chlorides, in particular with carbonyl chloride and oxalyl chloride (see Section III,C,4,b), is both conflicting and confusing and much of the work reported warrants repetition since the evidence presented in support of many of the structural assignments made is not entirel3 convincing. 

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