Mercuric Acetate allyl alcohol with

In another variant of such reactions, the hemi-acetal 104, generated in situ by reaction of the corresponding allylic alcohol with acetaldehyde, undergoes cyclization in the presence of HgClOAc to afford the mercurated acetal 105.128 Under these conditions, the reaction leads to the jy -product with a high selectivity (dr > 10 1 Scheme 14). The same strategy has been applied iteratively for the stereoselective synthesis of natural products containing 1,3,5,7,9-pentaether chains.129... 

The [3, 3] sigmatropic rearrangement of allyl vinyl ethers is known as Claisen rearrangement. Allylic alcohols can be converted to allyl vinyl ethers by mercuric acetate catalysed exchange with ethyl vinyl ether. The allyl vinyl ether need not be isolated because it undergoes rearrangement to 4-pentenal. 

Allyl vinyl ethers are usually obtained by either mercury salts or acid-catalyzed vinyl ether exchange with allylic alcohols, or acid-catalyzed vinylation of allylic alcohols with acetals. However, yields in these reactions are often low and care must be used when using mercury [1]. Mercuric salts of weak carboxyUc acids, for example, acetate, have been reported to be particularly effective in catalyzing the transfer of vinyl groups from vinyl ethers to alcohols (Eq. 3.1.1) [6]. 

Rather different are two N-alkylations effected with mercuric acetate 9-(3-oxobut-l-yl)carbazole (29 R = CH2CH2COCH3) was formed from car-bazole and but-l-en-3-yne in ethanolic solution containing a trace of concentrated sulfuric acid/° and a low yield of 9-allylcarbazole was produced on reaction with allyl alcohol in benzene... 

Unsaturation value can be determined by the reaction of the allyl or propenyl end group with mercuric acetate in a methanolic solution to give acetoxymercuric methoxy compounds and acetic acid (ASTM D4671-87). The amount of acetic acid released in this equimolar reaction is determined by titration with standard alcoholic potassium hydroxide. Sodium bromide is normally added to convert the insoluble mercuric oxide (a titration interference) to mercuric bromide. The value is usually expressed as meq KOH/g polyol which can be converted to OH No. units using multiplication by 56.1 or to percentage of vinyl using multiplication by 2.7. 

The quaternary center was constructed stereospecifically by Claisen rearrangement (Scheme 46). The necessary enol ether was obtained by reaction of the secondary alcohol of 399 with ethyl vinyl ether and mercuric acetate. To change the polarity of the endocyclic double bond, the unsaturated ketone was reduced with lithium aluminum hydride to the allylic alcohol, 400, at low temperature. Then, prolonged heating with xylene led to the aldehyde, 401. Protection of the secondary alcohol was achieved by bromoether formation with W-bromosuccinimide in acetonitrile before the aldehyde of 402 was reacted with methyllithium. The epimeric mixture of secondary alcohols was protected as acetates 403. Then, the cyclic ketone... 

It is possible to treat ketones with allyl alcohol and an acid catalyst to give y,8-unsaturated ketones directly, presumably by initial formation of the vinylic ethers, and then Claisen rearrangement. In an analogous procedure, the enolates (134) of allylic esters [formed by treatment of the esters with lithium isopropylcyclohexyla-mide (LICA)] rearrange to y,5-unsaturated acids. Allylic alcohols can be treated with a catalytic amount of mercuric acetate, and in the presence of an excess of allyl vinyl ethers give an alkene-aldehyde via a Claisen rearrangement. 

The corresponding iodide is prepared in a similar manner to the bromide. It may be crystallised from benzene or acetone and melts at about 80° C. It is more readily decomposed than the bromide, and hydrochloric or acetic acids break it down to allyl alcohol and mercuric salts. The presence of the two hydroxyl groups has been shown by the fact that the iodide yields a dibenzoyl derivative, M.pt. 100° C. When the iodide is treated with iodine at 40° C. a liquid iodohydrine is obtained. 

CARBONIC ACID, LITHIUM SALT (554-13-2) LijCOj Aqueous solution is an organic base. Violent reaction with acids. Inconpatible with fluorine, germanium, lead diacetate, magnesium, mercurous chloride, silicon, silver nitrate, titanium. Aqueous solution incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, cellulose nitrate, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, isocyanates, ketones, glycols, nitrates, phenols, vinyl acetate. Exothermic decomposition with maleic anhydride. Corrodes aluminum, copper, zinc in the presence of moisture. On small fires, use any extinguishing agent. 

Benzotriazole, allyl alcohol, mercuric acetate, and sulfuric acid monohydrate in benzene stirred and refluxed with azeotropic water-entrainment until water separation ceases after 5 hrs. —> N-allylbenzotriazole. Y 67%. F. e., with lower yields, s. H. Hopff and H. Liissi, Helv. 46, 1052 (1963). 

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