PUB - Publikationen an der Universität Bielefeld

A short synthetic route to protected alpha-methyl threonine 5 as a representative example for (protected) alpha-methylated alpha-amino-beta-hydroxy acids bearing a stereogenic quaternary carbon center in a-position was developed. This multistep synthesis is based on the use of an easily accessible prochiral starting material in the presence of an organocatalyst, and allows the access to all four types of stereoisomers. In addition, the first enantioselective acetyl migration in a Steglich rearrangement reaction as a key step in this multistep synthesis of 5 was achieved. The heterocycle 12, which was used in Steglich rearrangement reaction for the first time, turned out to be an efficient organocatalyst leading to an enantioselectivity of up to 63% ee.