Decalyl esters

Decalyl esters, aroma chemical derived from naphthalene, 3 235 Decamethylene diisocyanate,... 

In such a process, the water molecule fonned in the elimination step is captured primarily fiom the fixmt side, leading to net retention of configuration for the alcohol. For the ester, the extent of retention and inversion is more balanced, although it vari among individual systems. It is clear om die data in Table 5.18 that the two pairs of stereoisomeric amines do not form the same intermediate, even though a simple mechanistic interpretation would sugg that both would fmm the 2-decalyl cation. The coUap of the ions to product is pvidoitly so rapid that diere is not time for relaxation of the initially formed intermediates to reach a common stnicture. 

In 1944 Criegee observed that trans-9-decalyl peroxyesters rearrange on standing to 1,6-epoxycyclodecyl esters.172 Further study of the reaction showed that it has the characteristics of an ionic rather than a radical pathway The rate is... 

Diehotomous homolytie and heterolytie decomposition reactions can also be found in the thermolysis of peroxyearboxylie esters [195, 207-209] cf. Eq. (5-62) and Table 5-9 in Seetion 5.3.4. An already elassieal example, given in Eq. (5-150), is exhibited by the decomposition of tra s -9-decalyl peroxyphenylacetate [207]. 

The water molecule formed in the elimination step is evidently captured primarily from the front side, leading to retained configuration for the alcohol. The ester product can be formed by solvent collapse from the front or back side or by capture of the acetate ion. It is clear that the two stereoisomeric amines do not form the same intermediate, even though a simple mechanistic picture would show the 2-decalyl ion as a common intermediate. The product composition is very significantly different for the two starting materials. Similar results have been found for the cis-and 4-t-butylcyclohexylamines. Some of the data are summarized in Table 5.16. The general picture which arises from these and other diazotization studies then is one of a very rapid collapse of the cationic intermediate with the product ratio and stereochemistry determined by the immediate solvation environment. 

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