RESUMEN
An efficient and environmentally friendly procedure promoted by ultrasound irradiation is developed for stereoselective ring opening of various epoxides with aromatic and aliphatic amines under aqueous conditions in the presence of no catalyst or additive. Chemoselectivity of the protocol is shown by competition of piperidine and aniline to react with different epoxides resulting in exclusive formation of the respective products of piperidine.
RESUMEN
Various types of alcohols and phenols were rapidly protected by hexamethyldisilazane in good to excellent yields at room temperature using high-intensity ultrasound irradiation in the presence of no solvent or any additive. Good to excellent chemoselectivity was observed for competitive protection of hydroxyl groups in favor of sterically less hindered alcohols. Exclusive protection of phenols in the presence of aromatic amines was also demonstrated successfully.