10.1021/acs.orglett.7b02722.s001 Yasunori Toda Yasunori Toda Shuto Gomyou Shuto Gomyou Shoya Tanaka Shoya Tanaka Yutaka Komiyama Yutaka Komiyama Ayaka Kikuchi Ayaka Kikuchi Hiroyuki Suga Hiroyuki Suga Tetraarylphosphonium Salt-Catalyzed Synthesis of Oxazolidinones from Isocyanates and Epoxides American Chemical Society 2017 Epoxides Preparation tetraarylphosphonium salts enantioenriched N catalyze ylide regioselectivity acid aryl-substituted oxazolidinones Isocyanate role Br Tetraarylphosphonium Salt-Catalyzed Synthesis bifunctional ønsted isocyanate Mechanistic studies epoxide ring opening Oxazolidinone catalyst TAPS formation halohydrin 2017-10-17 16:22:49 Journal contribution https://acs.figshare.com/articles/journal_contribution/Tetraarylphosphonium_Salt-Catalyzed_Synthesis_of_Oxazolidinones_from_Isocyanates_and_Epoxides/5505829 Preparation of a range of oxazolidinones, including enantioenriched <i>N</i>-aryl-substituted oxazolidinones, in which tetraarylphosphonium salts (TAPS) catalyze the [3 + 2] coupling reaction of isocyanates and epoxides effectively, is described. The key finding is a Brønsted acid/halide ion bifunctional catalyst that can accelerate epoxide ring opening with high regioselectivity. Mechanistic studies disclosed that the ylide generated from TAPS, along with the formation of halohydrins, plays a crucial role in the reaction with isocyanates.