... Akio Baba,* Masahiro Fujiwara, and Haruo Matsuda Department of Applied Chemistry, Faculty of Engineering, Osaka University, Yamadaoka 2-1, Suita, Osaka 565, Japan Abstract Tetraphenyistibonium iodide is a general and versatile catalyst for the selective formation of unusual cycloadducts, 3,4-disubstituted oxazolidinones, in the reaction of oxiranes with isocyanates. ... 5. JE Herweh, WJ Kauffman, Tetrahedron Lett., 1971, 809. 6. ML Weiner, J. Org. ...