Enolate complexes overview

This part of the chapter gives an overview of different types of metal enolates, mainly -diketonates, with emphasis on the properties that can be of interest in analytical applications. The analytical applications of rare earth /3-diketonate complexes were reviewed . 

The selection of transition-state models suitable for rationalizing enolate formation by deprotonation, shown in this overview, give an impression of the complexity of a process that looked simple and convincing in Ireland s intuitive model. Nevertheless - despite all the differences in the deprotonation mechanisms of the various aggregates - its key idea, the cyclic arrangement, seems to be confirmed by the more recent studies. 

Chiral Metal Enolates in Aldol Reaction A general overview on common acetate aldol reaction using chiral metal enolates is given in Scheme 2.115. Both Masamune [18] and Corey [19] in their acetate aldol reaction use C2-symmetric boron complexes and as the acetate building block thio esters. Transformations with aldehydes usually provide enantiomeric ratios between 92 8 and 96 4 in good yields. More commonly used nowadays are Paterson s, Duthaler s, and Braun s acetate strategies. 

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