SPINOL-Derived Phosphoric Acids: Synthesis and Application in Enantioselective Friedel−Crafts Reaction of Indoles with Imines

A new class of chiral phosphoric acids with spirobiindane as scaffold were conveniently synthesized from (S)-1,1′-spirobiindane-7,7′-diol ((S)-SPINOL) and employed to catalyze the asymmetric Friedel−Crafts reaction of indoles with imines to afford 3-indolyl methanamines. High yields (68−97%) and excellent enantioselectivities (up to 99% ee) were obtained.