A series of novel chiral bifunctional tertiary amine–thioureas based on spirobiindane
were designed and synthesized as organocatalysts. One of these catalysts was shown
to promote the asymmetric Michael addition reaction of 1,3-diphenylpropane-1,3-dione
to nitroolefins, affording the desired products in good yields (up to 95%) and enantioselectivities
(up to 98% ee).
Key words
organocatalysis - Michael addition - nitroolefins - spiro skeleton - thiourea