4-Hydroxymethyl-substituted oxazolidinone synthesis by tetraarylphosphonium salt-catalyzed reactions of glycidols with isocyanates.

Preparation of 4-hydroxymethyl-substituted oxazolidinones including optically active ones, in which tetraarylphosphonium salts catalyze the reaction of glycidol with isocyanates effectively, is described. The neutral catalysis facilitates glycidol addition to isocyanates followed by intramolecular cyclization. Mechanistic studies suggest that hydrogen-bonding interactions with the catalyst play an important role in the reaction progress.

Use of trichloroacetonitrile as a hydrogen chloride generator for ring-opening reactions of aziridines.

Regioselective ring-opening reactions of 2-aryl-N-tosylaziridines are described, in which hydrogen chloride is generated by photodegradation of trichloroacetonitrile. HCl adducts are obtained in high yields in 1,4-dioxane, whereas methanol adducts are predominantly obtained in methanol. Trichloroacetonitrile can serve as a photoresponsive molecular storage generator for hydrogen chloride.

Tetraarylphosphonium Salt-Catalyzed Synthesis of Oxazolidinones from Isocyanates and Epoxides.

Preparation of a range of oxazolidinones, including enantioenriched N-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.