Enantioselective Aldol Reactions Catalysed by N-Toluenesulfonyl-L-proline Amide in Ionic Liquids.

N-Toluenesulfonyl-L-proline amide was tested as catalyst in the enantioselective aldol addition of acetone to aromatic aldehydes in different ionic liquids. The aldolisation products were isolated in high yields (up to 98%) with enantioselectivities ranging from 50 to 90% Immobilisation of the catalyst in ionic liquids allows simple product isolation and repeated use. The chemical yields and enantioselectivities achieved were comparable to those obtained when using this catalyst in DMSO. Overall, the trends regarding enantioselectivity and yields are comparable to those using L-proline as catalyst in ionic liquids.