Stobbe reaction deprotonation

Instead of epoxides carbonyl compounds may be used as electrophiles to generate the y-hydroxy carboxylic acid intermediate. In the classical Stobbe reaction (equation 79) succinic esters are deprotonated and treated with aldehydes or ketones to form, via the unstable adduct (211), the paraconic ester (212). 

A more recent and stereocontrolled version of the Stobbe reaction is shown in equation (80). 3-Lac-tone ester (213) is deprotonated to the enolate (214), which adds aldehydes to give either monocyclic... 

The first step of the Stobbe condensation is the deprotonation of the succinate at the a-carbon to afford an ester enolate that in situ undergoes an aldol reaction with the carbonyl compound to form a 3-alkoxy ester intermediate. The following intramolecular acyl substitution gives rise to a y-lactone intermediate which undergoes ring-opening and concomittant double bond formation upon deprotonation by the alkoxide ion. Under certain conditions the lactone intermediate can be isolated. 

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See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ ]

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