Transmetallation nitrogen nucleophiles

Oxazolidinone-Substituted Carbanions. Oxazolidinone-substituted organostannanes readily undergo transmetalation with alkyllithium reagents to the organolithium derivatives which then can undergo nucleophilic addition reactions. -Substituted oxazolidinones can act in this capacity as both a nitrogen source and source of chirality (eq 60). Although the a-stereoselection... 

As seen with the previous example, activation of the organostannane to promote the transmetalation step has a dramatic and positive influence on the outcome of the reaction. In 1992, Vedejs et al. showed that intramolecular coordination of tin by a nucleophilic center like a nitrogen can considerably increase the rate of the transmetalation step in the Stille coupling . Derivatives like 22 proved to be more reactive than their analogue trialkyl tin... 

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