Alkylzinc compounds

Alkylzinc compounds bearing -hydrogens reduce allyl acetates on treatment with Pd° (equation 106).304... 

Allyl ketones can be prepared by trapping acylpalladium intermediates with main group metal compounds. The allyl ketone 251 can be prepared from the allyl ester 248 by trapping acylpalladium 249 with the alkylzinc compound 250 at room temperature and 1 atm [115]. Reaction of geranyl chloride (252) with the furylstannane 253 under CO pressure afforded the ketone 254, which was converted to dendrolasin (255) [93]. Aldehydes are prepared by trapping with a metal hydride. The /l,y-unsaturated aldehyde 257 is prepared by the carbonylation of the allyl chloride 256 in the presence of Bu3 SnH [116,117],... 

Table 6 Selected average bond lengths and bond angles for some dimeric alkylzinc compounds...

Alkylzinc Compounds Containing a Zinc-Oxygen Bond... 

There are two principal classes of alkylzinc compounds containing a zinc-oxygen bond, that is, those derived from aliphatic and aromatic alcohols (commonly called alkylzinc... 

In some cases, alkylzinc compounds containing oxygen are subject to redistribution equUibria. This is shown in solution by the presence of different species. For example, compounds of general formula R6Zn7(OMe)g can be isolated from solutions of [RZn(OMe)]4 (R = Et, Me). The structure ofthese aggregates, as shown in Figure 34, consists of two Zn404 cubic... 

The use of indole salts is frequently required to achieve selective attack at the 3-position in the acylation reaction. However, this approach is not applicable to indoles bearing functional groups labile under basic conditions, and consequently, Grignard reagents or alkylzinc compounds cannot be used for the preparation of the indole salts as shown in Scheme 2.2. A second approach involves the use of N-protected indoles and requires protection-deprotection steps. 

Frankland 1849. The zinc-tradition in preparative organic chemistry had its start when Edward Frankland [2] discovered the formation of alkylzinc compounds from the reaction of iodoalkanes with metallic zinc ... 

Frankland 1855. Diethylzinc Purified. From his third publication in 1855 [4], it appears that Frankland had several unpleasant experiences with the preparation of the alkylzinc compounds. He made mention of a new apparatus, constructed by an engineer, in which he could easily prepare 4 to 5 ounces of diethylzinc which he mainly used for analytical purposes. Furthermore it is worth noting that... 

A wide variety of typical anionic initiators is described for the polymerization of PMVK. Grignard reagents are used as well as complexes formed of alkylaluminum or alkylzinc compounds with alkali metal alkyls (so called -ate complexes ). Alkali metal initiators and alkoxides are also described. Some examples are given in Table 5. 

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