Development of a Chiral Bis(guanidino)iminophosphorane as an Uncharged Organosuperbase for the Enantioselective Amination of Ketones

Chiral bis­(guanidino)­imino­phosphoranes were designed and synthesized as chiral uncharged organo­superbase catalysts that facilitate activation of less-acidic pro-nucleophiles. The newly developed bis­(guanidino)­imino­phosphoranes, which possess the highest basicity among chiral organocatalysts reported to date, were proven to be a superb class of chiral organo­superbases by reaction of azodicarboxylates with 2-alkyltetralones and their analogues as the less acidic pro-nucleophiles.