Asymmetric Synthesis of 2,4,5-Trisubstituted Delta super(2)-Thiazolines

Delta super(2)-Thiazolines are interesting heterocycles that display a wide variety of biological characteristics. They are also common in chiral ligands used for asymmetric syntheses and as synthetic intermediates. Herein, we present asymmetric routes to 2,4,5-trisubstituted Delta super(2)-thiazolines. These Delta super(2)-thiazolines were synthesized from readily accessible/commercially available [alpha],[beta]-unsaturated methyl esters through a Sharpless asymmetric dihydroxylation and an O arrow right N acyl migration reaction as key steps. The final products were obtained in good yields with up to 97% enantiomeric excess. Paving the way: A route to 2,4,5-trisubstituted Delta super(2)-thiazolines has been developed by starting from [alpha],[beta]-unsaturated methyl esters, with a dihydroxylation and tandem azide reduction/O arrow right N acyl migration reaction as key steps (see figure). Asymmetric versions of the reaction have also been developed with use of the Sharpless asymmetric dihydroxylation to give the final products in high enantiomeric excess.