Organocatalytic Asymmetric α‐Aminoxylation/Aza‐Michael Reactions for the Synthesis of Functionalized Tetrahydro‐1,2‐oxazines

Catalyst for THOught: The title reaction using acyclic nitroalkenals for the asymmetric installation of both CO and CN bonds led to functionalized tetrahydro-1,2-oxazines (THOs) having up to three stereogenic centers; the products were isolated in up to 90 % yield with excellent enantioselectivity and complete diastereoselectivity (see scheme). DFT calculations reveal an unprecedented transition state containing a molecule of water, which assists in the CN bond-forming step by participating in two hydrogen bonds.