Enantiotopic leaving group, nucleophilic substitution

It should be noted that Trost s DPPBA-derived ligand 21 possesses considerable utility in many other situations of allylic substitution, for example with substrates which are cyclic or which possess enantiotopic leaving groups, or with prochiral nucleophiles.1171... 

An enantioselective method in which a chiral catalyst is responsible of a desymmetrizing nucleophilic aromatic substitution through discrimination in the displacement of an enantiotopic leaving group has been reported very recently in the heterocyclic series. Under PTC conditions, the chiral counterion 113 (10% mol) directs the substitution of prochiral dichloropyrimidine 112 by PhSKby a tandem desymmetrization/kinetic resolution mechanism, leading to the chiral product 114 (Scheme 8.23) [87]. 

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