Addition of Enolates with a-Substituents to Aldehydes

As described previously, vhen enolates have a-substituents, new a- and f-chiral centers are formed. Thus, it is possible to form aldol products in vhich the a- and j5-substituents are in a syn or anti relationship to each 

Chiral auxiliaries used in the stereoselective acetate aldol reactions described in Table 2.6. 

Bromination-aldol reaction and reductive debromination-deprotection. 

Methods have been developed to provide both diastereoselectivity and enantioselectivity in the aldol products. These developments are not mere extensions of previous methods. In fact, many titanium enoiate-based asymmetric transformations provide stereoselectivity and efficiency tvhich cannot be obtained by use of other methods. 

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Addition of Enolates with a-Substituents to Aldehydes 103 TsNH... 

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