A Tunable Cascade Reaction of Ureidomalonates and Alkenyl Azlactones for the Divergent Synthesis of Hydantoins with Distinct Functional Groups

A tunable cascade reaction of ureidomalonates and alkenyl azlactones was disclosed, which gave rise to the construction of N-aroyl α-amino acid ester and imide-functionalized hydantoins in moderate to good yields and with excellent diastereoselectivities. The reaction pathway was precisely manipulated by organocatalysis and phase-transfer/sunlight relay catalysis, respectively, to realize the divergent synthesis. The successful gram-scale preparation of representative products exhibited the application potential of this protocol. Mechanistic studies indicated that the exchange and phase transfer of ethoxy anion played a key role in altering the reaction pathway, and sunlight might accelerate the oxidation process at the late stage of the reaction triggered by phase-transfer catalysis.