A new method for the Brønsted acid-catalyzed addition of amide nucleophiles to imines to produce protected aminal products is described. Simple Brønsted acids (phenyl phosphinic acid and trifluoromethanesulfonimide) were shown to be excellent catalysts, providing high yields of the aminal product. A catalytic asymmetric imine amidation using sulfonamides as nucleophiles was successful when a hindered biaryl phosphoric acid catalyst derived from 2,2'-diphenyl-[3,3'-biphenanthrene]-4,4'-diol (VAPOL) was used. Excellent yields and enantioselectivities were found in these additions (up to 99% ee).

The enantioselective ring-opening of meso-aziridines with azide nucleophiles proceeded in the presence of a catalytic amount of a chiral phosphoric acid catalyst. The reaction affords the formation of the products in excellent yield and enantioselectivity. Preliminary mechanistic studies indicate that the active catalytic species is a chiral silane that is generated in situ.

A highly enantioselective Friedel-Crafts reaction of pyrrole derivatives with N-acyl imines catalyzed by chiral phosphoric acids was developed. The reactions produced the pyrrole derivatives in high yields and enantioselectivity.

The first highly enantioselective catalytic method for the preparation of chiral aminals via the addition of imide nucleophiles to imines is reported.

The highly enantioselective organocatalytic addition of N-benzyl indoles to N-acyl imines is reported. A total of 15 examples with product yield ranging from 89% to 99% and enantioselectivities from 90% to 97% are presented. A chiral phosphoric acid catalyst derived from a hindered binol derivative was employed most effectively in the reaction. Attractive features of the reaction include desirable catalyst loadings, good reactivity, generality of substrates, and easily removable groups from both nitrogen atoms.