Zinc alkoxides synthesis

DNA polymerases, 5, 1007 Trans effect, 1,16, 26, 315 metal complexes, 2, 705, palladium(II) amine complexes, 5, 1115 platinum complexes, 5, 353, 493 six-coordinate compounds. 1, 49 T ransestcrification metal alkoxide synthesis, 2, 340 Transferases zinc, S, 1002... 

The zinc alkoxides of syn- or /7-3-(/3-hydroxyacyl)oxazolidin-2-ones underwent stereoselective rearrangement under mild conditions to afford syn- or /7-3-(2-hydroxyethyl)tetrahydro-l,3-oxazine-2,4-diones in good yields. The procedure was utilized in the synthesis of ( )-trisubstituted 0 ,/3-unsaturated amides and acids <2005OBC2976, 2005SL1090>. 

A continuous process has been described (14) which can produce either the amide or the nitrile by adjusting the reaction conditions. Boric acid has been used as a catalyst in the amidation of fatty acid (15). Other catalysts employed include alumina (16), titanium, and zinc alkoxides (17). The difficulty of complete reaction during synthesis has been explained by the formation of RCOOH RCOO, a stable intermediate acid ammonium salt (18). 

As with aldehydes, catalytic additions to ketones are more promising with less polar organometallics and some enantioselective catalytic organozinc additions to ketones have been developed [96,97]. For the synthesis of efavirenz (23), stoichiometric amounts of chiral zinc alkoxide additives proved to be highly useful. 

Klaus M, Stefan B, Robert S, Matthias D. Facile synthesis and structural variation of novel heterobimetallic alkali metal-zinc-alkoxide and-siloxide clusters. J Chem Soc Dalton Trans 2003 3365-9. 

Chamberlain et al. [13] prepared a series of zinc alkoxide complexes that act as single-site living initiators for the polymerization of DLA or LLA to isotactic PLA, rac-LA to atactic PLA, and mcra-LA to syndiotactic PLA. The synthesis of chiral aluminum and yttrium alkoxides as stereospecific catalysts used for LA polymerization has also been reported by Ovitt and Coates [14]. 

Walsh developed a highly enantio- and diastereoselective one-pot method for the efficient synthesis of acyclic epoxy alcohols and allylic epoxy alcohols [263]. This method took the advantage of a highly enantioselective C-C bond-forming reaction to set the initial chirality. The resulting allylic zinc alkoxide intermediate is then epoxidized in situ using either O2 or TBHP in the presence of a titanium... 

CF3CCl2-substituted alcohols in good yields. In this case, when insitu-geaeiaied zinc alkoxides are subsequently treated with AC2O and zinc dust at 50°C, trifluoromethylated alkenes can be obtained in good yields (Scheme 26.33). This practical one-pot synthesis can be applied for the preparation of highly potent insecticides, so-called synthetic pyrethroids, such as bifenthrin and others. ... 

Previously published methods for the synthesis of dimethylzinc, a useful alkylating agent, include the reaction of dimethylmercury with metallic zinc,1 the reaction of a zinc-copper couple with methyl iodide,2 and the Grignard method.3 The reaction of trimethylaluminum with zinc(II) halides or alkoxides can be used,4 but it is more convenient to use zinc(ll) acetate, which is very readily obtained by dehydrating the commercial dihydrate with boiling acetic anhydride or by the reaction5 ... 

At a considerably later date. Frankland prepared ethyl methacrylate and methacrylic acid from ethyl a-hydroxyisobutyrate and phosphorus trichloride. Tollen prepared aciylate esters from 2,3-dibromopropionate esters and zinc. Otto Rohm, in 1901. described the structures of the liquid condensation products (including dimers and timers) obtained from the action of sodium alkoxides on methyl and ethyl acrylate. Shortly after World War 1, Rohm introduced a new acrylate synthesis, noting that an acrylate is formed in good yield from heating ethylene cyanohydrin and sulfuric acid and alcohol. A major incentive for the development of a clear, tough plastic acrylate was for use in the manufacture of safety glass. 

In the presence of a Mannich base, hydroxymethyl derivatives 268 may behave, in turn, as alcoholic reagents, thus affording amino group replacement with formation of the symmetrical ether 269 (R = R —CH ). Indeed, alcohols and phenols allow the synthesis of ethers 269, starting from phenolic Mannich bases as well as from the methiodides of aminomethylfcrrocenes, by reaction with alkoxide or phenoxide. Good results have been obtained with a thioporphirine Mannich base and zinc acetate. Esters 270 (Fig. 102) can be synthesized from various Mannich bases such as those derived from tropolones or purines, which are converted into acetoxymethyl... 

This method has been utilized for the synthesis of alkoxides of zinc and cadmium as well as the lanthanides with some specially hindered alcohols (cf. Section IV). 

Kim, S. M. Kim, C.-S. Ha, D.-W. Park, Synthesis and cyclohexene oxide/carbon dioxide copolymerizations of zinc acetate complexes bearing bidentate pyridine-alkoxide ligands, Macro-molec. Rapid Commun. 25 (2004) 888. 

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