Boronate assemblies

Unless there is a chiral ligand on boron, assemblies a and b of Scheme 5.2 are enantiomeric and the product will be racemic. If the ligand is chiral, then the transition structures are diastereomeric and the products will be formed in unequal amounts under conditions of kinetic control (Chapter 1). Figure 5.1 illustrates several chiral boron reagents that have been tested in the allyl boration reaction, with typical enantioselectivities for each. 

Assemblies relying on the dative B-N interaction in conjunction with boronate ester formation to form linear polymers have also been identified. Unlike the stepwise phenanthroline-boronate assembly, esterification coupled with ligation occurs simultaneously. In fact, it is likely that coordination... 

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