Ester dienolates

J. Rodriguez et al. have investigated the stereoselective ester dienolate Carroll rearrangement of ( )- and (Z)-allylic (3-keto esters and found a new, attractive approach to the synthesis of the Prelog-DJerassi lactone and related... 

Ouvrard, N., Rodriguez, J., Santelli, M. Stereoselective ester dienolate Carroll Rearrangement a New Approach to the Prelog-Djerassi lactone framework. Tetrahedron Lett. 1993, 34, 1149-1150. 

Hiersemann, M., Abraham, L., Pollex, A. The ester dienolate [2,3]-Wittig rearrangement - development, opportunities, and limitations. SynleU 2003,1088-1095. 

Reaction of zinc ester dienolates with simple aldehydes and ketones... 

It seems reasonable to conclude that, as originally proposed by Gaudemar, one-stage Reformatsky reactions of zinc ester dienolates will produce mainly a-products in kinetically controlled processes, and... 

Reaction cfzinc ester dienolates with conjugated enones 287... 

On base catalysis, / ,y-unsaturated esters are converted to the thermodynamically stable a,/ -iso-mers. However, ester dienolates prepared from the x,/j-unsatu rated esters (or from the j ,y-iso-mers) can be protonated under kinetic control in the a-position to yield the /hy-unsaturated esters105 (see also dienolates, Section 2.1.3.5.). 

Hiersemann has reported the synthesis of 2-hydroxy-y-lactones 77 by the [2,3]-Wittig rearrangement of ester dienolate substrates 75 and 76. The products of the rearrangements were required as substrates for 3-oxy-Cope rearrangements, ultimately leading to the stereoselective synthesis of nonnatural amino acids. ... 

Several examples of the ester dienolate [2,3]-Wittig rearrangement have been investigated in order to gain some insight into the factors that determine the... 

Stereochemical outcome of this rearrangement. Enolization of the regioisomeric esters (127) and (128) has been shown to afford a-allyloxy-substituted ester dienolates (129) which undergo a [2,3]-sigmatropic rearrangement to yield 3-alkoxycarbonyl-3-hydroxy-substituted hexa-1,5-dienes (130). These have been transformed to diastereomerically pure 2,3-dialkenyl-substituted (/-lactones (131). 

Kende, A. S. and Toder, B. H., Stereochemistry of deconjugative alkylation of ester dienolates stereospecific total synthesis of the htsenoHdes, /. Org. Chem., 47,167,1982. 

This type of cyclization of ethyl ester dienolates provides bicyclic ketones and was recently used for the preparation of carbacycline [87]. 

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