Aminal-Pyrrolidine Organocatalysts - Highly Efficient and Modular Catalysts for α-Functionalization of Carbonyl Compounds

The substitution of the 4-position of hydroxyproline by a phenol group, together with an aminal on the 2-position, gave a synergistic effect leading to two powerful complementary organocatalysts. They show excellent enantiocontrol in the alpha-functionalization of a wide range of linear/branched aldehydes and ketones, including Michael additions to ethenediyl disulfones or nitrostyrene and alpha-amination. We obtained ees up to 98.5% with low catalyst loadings (down to 1 mol-%). As a proof of efficiency, TOFs of up to 1000 h(-1) could be obtained.