Stereoinduction from a chiral Lewis acid

An advantage of the Mukaiyama aidol reaction is that chiral Lewis acids can be used to obtain asymmetric induction. This is especially efficient as the reactions can proceed with as little as 0.5 mol% catalyst. Such reagent turnover is normally 

Two related chiral Lewis acids are the acyloxyborane 68 [46] and the oxazabo-rolidine 69 [47] which are derived from (/ ,/ )-tartrate and L-valine, respectively. Each uses borane to generate the active catalyst, and they promote a variety of 

9 Stereoselective Aldol Reactions in the Synthesis of Polyketide Natural Products 

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