Boron and Silicon Enolates in Crossed Aldol Reaction

Boron and Silicon Enolates in Crossed Aldol Reaction 

Metal enolates play an important role in organic synthesis and metal enolate-mediated aldol type reactions, in particular, are very useful synthetic tools in stereoselective and asymmetric carbon-carbon bond formation. Generation and reactions of different metal enolates have been extensively studied and successful applications to the controlled formation of carbon-carbon bonds have been realized under mild conditions. 

The aldol reaction has long been recognized as one of the most useful synthetic tools. Under classical aldol reaction conditions, in vhich basic media are usually employed, dimers, polymers, self-condensation products, or a,j5-unsaturated carbonyl compounds are invariably formed as byproducts. The lithium enolate-mediated aldol reaction is regarded as one useful synthetic means of solving these problems. Besides the vell-studied aldol reaction based on lithium enolates, very versatile regio- and stereoselective carbon-carbon bond forming aldol-type reactions have been established in our laboratory by use of boron enolates (1971), silicon enolates-Le vis acids (1973), and tin(II) enolates (1982). Here we describe the first t vo topics, boron and silicon enolate-mediated crossed aldol reactions, in sequence. 

Crossed Aldol Reactions Using Boron Enolates 

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I 3 Boron and Silicon Enolates in Crossed Aldol Reaction... 

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