Use of the Claisen/metathesis reaction sequence for the synthesis of enantiomerically pure 1-aminocycloalkene-1-carboxylic acids

An effective method for the preparation of enantiomerically pure 1-aminocycloalkene-1-carboxylic acids is reported using a chelate Claisen rearrangement–metathesis sequence. Enantioselectivity is achieved through substrate control and a highly ordered transition state, without the use of a chiral auxiliary. A synthesis of 1-aminocyclopent-3-ene-1-carboxylic acid 1 in five steps and 47% overall yield is also described.