Synthesis and catalytic properties of 4-aryl-2,3-dihydro-4H-pyrimido[2,3-b]benzothiazoles for asymmetric acyl or carboxyl group transfer reactions.

4-Aryl-2,3-dihydro-4H-pyrimido[2,3-b]benzothiazoles (4-Ar-DHPBs) were synthesized and their catalytic activity and selectivity in kinetic resolution of a secondary alcohol as well as in the Steglich rearrangement and related reactions were evaluated. 4-Aryl-DHPBs showed low enantioselectivity in the acylative kinetic resolution of 1-phenylethanol. Conversely, they catalyzed the Steglich rearrangement with moderate to excellent enantioselectivity, demonstrating the possibility for remote stereocontrol by introduction of a substituent at the 4-position of DHPB.