Stereoinduction from a chiral ketone

This is the most common form of substrate control in asymmetric aldol reactions. In general, Ti-facial discrimination arises from the n-stereocenter of the enolate component however, there are many cases where a / -oxygen substituent plays an important role. 

We have shown that useful levels of 1,4-asymmetric induction can be achieved with the boron enolate 10, derived from methyl ketone 11 [6J, in which a variety of protecting groups can be accommodated (e.g. TBS, TIPS, Bn, PMB) 

9 Stereoselective Aldol Reactions in the Synthesis of Polyketide Natural Products 

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