Formal nucleophilic substitution of bromocyclopropanes with amides en route to conformationally constrained ß-amino acid derivatives.

A chemo- and diastereoselective protocol for the formal nucleophilic substitution of 2-bromocyclopropylcarboxamides with secondary amides is described. This method allows for convergent and highly selective synthesis of trans-ß-aminocyclopropane carboxylic acid derivatives.