Triple Role of Phenylselenonyl Group Enabled a One-Pot Synthesis of 1,3-Oxazinan-2-ones From α‑Isocyanoacetates, Phenyl Vinyl Selenones, and Water

Reaction
of α-substituted α-isocyanoacetates with phenyl
vinyl selenones in the presence of a catalytic amount of base (DBU
or Et3N, 0.05–0.1 equiv) followed by addition of p-toluenesulfonic acid (PTSA, 0.1–0.2 equiv) afforded
4,4,5-trisubstituted 1,3-oxazinan-2-ones in good to excellent yields.
Enantiomerically enriched heterocycles can also be prepared using
a Cinchona alkaloid-derived bifunctional organocatalyst
for the Michael addition step. The phenylselenonyl group served as
an activator for the Michael addition, a leaving group and a latent
oxidant in this integrated reaction sequence.