Chiral p-keto imides

Besides alkyl halides, other electrophiles have been allowed to react with the imide-derived enolate (165). For example acylation of (165) with propionylchloride afforded the chiral P-keto imide (177) in 95% yield with high stereoselectivity 17S). 

The Evans aldol reaction using chiral p-keto imide 23 as a dipropionate building block is also very effective for the construction of polypropionate segments in polyoxomacrolides (Scheme 2) [8]. The diastereoselective aldol reaction of 23 via different metal enolates (Ti, Sn, and B enolates) afforded three kind of aldols, syn-syn-24, anti-syn-25, and anti-anti-26, with high diastereoselectivity, respectively. The subsequent stereoselective reduction of the resulting p-hydroxy ketones 24-26 provides various types of dipropionate units. Based on this strategy, the... 

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