Ester with tertiary alkyl group

Hydrolysis of Esters with Tertiary Alkyl Groups... 

Esters with tertiary alkyl groups undergo hydrolysis much more rapidly than do other esters because they hydrolyze by a completely different mechanism—one that does not involve formation of a tetrahedral intermediate. The hydrolysis of an ester with a tertiary alkyl group is an SnI reaction because when the carboxylic acid leaves, it leaves behind a relatively stable tertiary carbocation. 

In general, aliphatic diacyl peroxide initiators should be considered as sources of alkyl, rather than of aeyloxy radicals. With few exceptions, aliphatic acyloxy radicals have a transient existence at best. For certain diacyl peroxides (36) where R is a secondary or tertiary alkyl group there is controversy as to whether loss of carbon dioxide occurs in concert with 0-0 bond cleavage. Thus, ester end groups observed in polymers prepared with aliphatic diaeyl peroxides are unlikely to arise directly from initiation, but rather from transfer to initiator (see 3.3,2.1.4),... 

Since 1971, we have been engaged in the synthesis of g-substituted dialkyl N-nitrosamines, namely -hydroxy N-nitrosamines. Because of the presumed high reactivity of these alcohols, it seemed desirable to have them in a stabilized form, e.g. as esters. In 1970 Franck and his group reported a method to convert tertiary amines into dialkyInitrosamines in the presence of 2-nitropropane, cuprous ion and oxygen 9). If the amine is substituted with different alkyl groups, these groups are cleaved statistically (Eq. 1). 

A., 297, 92 B., 36, 3678 38, 714, 1934.) Both assumptions coincide equally well with the fact that fatty acid esters do not condense analogously to the above, with secondary and tertiary alkyl groups. 

Preparation of ethers. Treatment of secondary and tertiary alcohols with dimsylsodium in DMSO followed by alkylation with a dialkyl sulfate gives ethers in 60-90% yield. The presence of ester and tertiary amino groups and of double bonds docs not interfere with the reaction. However, alkylation of a- or j8-hydroxyketones was not successful by this procedure. 

Hydrolysis of An Ester with a Tertiary Alkyl Group... 

MECHANISM FOR THE HYDROLYSIS OF AN ESTER WITH A TERTIARY ALKYL GROUP... 

The hydrolysis of an ester with a tertiary alkyl group... 

Primary alkyl groups are more reactive than secondary and tertiary. PivaUc acid accelerates the rate of protonolysis of trialkylboranes with water and alcohols (207,208). The reaction can be controlled to give excellent yields of dialkylbotinic acids and esters. 

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