Bimorpholine-mediated enantioselective intramolecular and intermolecular aldol condensation.

Monosalts of N-substituted bimorpholine derivatives are efficient organocatalysts in intramolecular and intermolecular aldol reactions. The properties of the catalysts can be tuned either by the selection of an appropriate acid for the salt formation or by the change of a substituent at the nitrogen atom. In aldol condensation, i-Pr-substituted bimorpholine is the most stereoselective catalyst affording products in high yield with enantioselectivities up to 95% ee.