Aryl bisamide

If R2 contains an a-hydrogen the method cannot be applied as enaminc formation occurs. Bisamides (or -carbamates) are often used in amidoalkylations of aryl and reactive methylene compounds, but the rather harsh reaction conditions severely limit application in the synthesis of more complicated molecules with other functional groups. 

These are somewhat similar to the alkyl or aryl compounds, being mononuclear with bulky ligands and dinuclear with less bulky ones. Examples are (8-XXIV) and (8-XXV). The orange Ge(NBu2)2 is stable but the maroon tin analogue is thermo-and photosensitive. Metathetical exchange166 between carbon dioxide and bisamides... 

Mg enolates generated from Mg bisamides can be used in aldol addition reactions with alkyl, aryl, and cyclic ketones. As shown in Scheme 3.40, these reactions are significant in that the self-coupling of ketones in aldol reactions to give tertiary yS-hydroxyketones are also possible. More specifically, these transformations are achieved principally by the use of relatively high reaction temperatures between 25 °C and 60 °C. Such conditions are a notable departure from the widely used lithium-mediated aldol additions, where increasing the reaction temperature results in retro-aldol processes and also elimination of LiOH to give enone products [30]. 

A number of such ligands have been developed. They typically include a diphenylphosphino aryl unit connected to a chiral group. Bisamides 9.128 derived from rran5-l,2-diaminocyclohexane, and also other diamines, have proved valuable, as have phosphinooxazoline derivatives, such as 9.129. ... 

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