Organolithium reagents chiral ketones

These reagents add to the chiral ketones 3 with high 1,5-asymmetric induction. Grignard and organolithium reagents show slight diastereoselectivity.3 Example ... 

In general, nucleophilic addition reactions using Grignard or organolithium reagents to -chiral or other remotely chiral ketones usually yield mixtures of stereoisomers which are not synthetically use-fiil.9,12-27 However, some specific examples of stereoselective organolithium and Grignard additions to these remotely chiral carbonyl compounds have been reported. 

Chiral boronic esters react with organolithium reagents to form diorganylalkoxyboranes (borinic esters). Subsequent reaction with the anion of dichloromethyl methyl ether then yields chiral ketones by rearrangement of both of the groups on boron (Scheme 42). No racemization is observed in this sequence and alkyl-, aryl- or alkynyl-lithium reagents can be used. 

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