Asymmetric organocatalysed [1,3]-sigmatropic rearrangements

Article abstract of DOI:10.1002/chem.200701729

The first organocatalysed enantioselective [1,3]-sigmatropic O- to N-rearrangement reactions are presented. The reactions take place under regio- and enantioselective control, and are catalysed by cinchona alkaloids. Two reactions have been developed the first one is the rearrangement of imidates to amides, while the other rear rangement occurs from carbamates to amines via a decarboxylation. Both transformations give nitrogen protected β-amino acid derivatives as the product. These novel asymmetric organocatalysed [1,3]-sigmatropic O- to N-rearrangement reactions provide a reliable and efficient synthetic method for obtaining enantioenriched β-amino acid derivates in good yield from racemic starting materials.