Synthesis of 1,1-Spirobiindane-7,7-Disulfonic Acid and Disulfonimide: Application for Catalytic Asymmetric Aminalization

1,1-Spirobiindane-7,7-disulfonic acid (SPISA) and 1,1-spirobiindane-7,7-disulfonimide were synthesized from 1,1-spirobiindane-7,7-diol (SPINOL) in 4 steps using a Pd-catalyzed Newman-Kwart rearrangement as a key step. These new catalysts possessing a rigid spirocyclic backbone were evaluated in a catalytic asymmetric aminalization reaction, and SPISA/iPr(2)NEt exhibited high enantioselectivity, demonstrating the utility of SPISA as a chiral BrOnsted acid catalyst.