Synthesis and Reactivity of 3-Oxazolines3-Oxazolines 1 have been prepared from a-hydroxy aldehydes, ammonia, water and a second 0x0 compound (aldehyde or ketone) in a one-pot reaction. Carboxylic acid chlorides add to the azomethine bond of 1 to yield 3-acyl-4-chlorooxazolidines 2. 4-Hydroxy and 4-alkoxyoxazolidines 3 are obtained from 2 upon treatment with aqueons sodium hydroxide or alkanol/ triethyl amine, respectively. Some oxazolidines 3 are formed with high diastereoseselectivity.