Asymmetric Organocatalytic Formal Aza‐Michael Addition of Ammonia to Nitroalkenes

The formal addition of ammonia to nitroalkenes, affording optically active β-amino nitro compounds in high yields and enantioselectivities, is presented (see scheme). The approach is based on a novel thiourea-catalyzed aza-Michael reaction, by which benzophenone imine serves as a masked ammonia equivalent, which is released by hydrolysis.