Chemo- and Regioselective 4CR Synthesis of Oxathiaaza[3.3.3]propellanes via Sequential C–S, C–N and C–O Bond Formation in a Single Pot

Oxathiaaza[3.3.3]propellane derivatives were prepared by reaction of in situ generated asymmetric thioureas with inter­mediate Knoevenagel adducts resulting from ninhydrin and malononitrile. This four-component sequential transformation performed in one reaction flask represents a general route to this unexplored valuable class of sulfur–nitrogen heterocycles. The chemoselectivity and regiochemistry of the products were established by IR, NMR and single crystal X-ray analysis.