Optically active 1,1'-spirobiindane-7,7'-diol (SPINOL)-based phosphoric acids as highly enantioselective catalysts for asymmetric organocatalysis.

The synthesis and application of a series of optically active 1,1'-spirobiindane-7,7'-diol (SPINOL)-based phosphoric acids are described. These SPINOL-based phosphoric acids were prepared from (R)-SPINOL in three steps and exhibited excellent enantioselectivities for the reactions of indoles with aldimines and β,γ-unsaturated-α-ketoesters. Our study provides a family of promising chiral phosphoric acids to the asymmetric organocatalysis toolbox.