d-Mannitol-derived novel chiral thioureas: Synthesis and application in asymmetric Henry reactions

Five novel thioureas have been obtained through multi-step reactions from d-Mannitol as starting material and applied as catalysts in the asymmetric Henry reaction. Using catalyst 7a, (1S,2R)-2-nitro-1-phenylpropan-1-ol containing two chiral centers was obtained in high yield and with high selectivity (up to 95% yield, 87% ee, 91:9 dr). This catalyst also retained activity in the presence of water, affording a up to 93% yield, 88% ee, and 94:6 dr.