Stereocontrolled synthesis of (2S*,3R*,4R*)-4-hydroxy-3-methylproline using a silicon assisted aza-[2,3]-Wittig sigmatropic rearrangement

Abstract

The first racemic synthesis of the non-proteinogenic amino acid (2S,3R,4R)-4-hydroxy-3-methylproline (1) has been achieved via iodolactonisation of an unnatural amino acid derivative 4. The relative stereochemistry was derived from an efficient silicon assisted aza-[2,3]-Wittig sigmatropic rearrangement of 2.