Highly diastereoselective synthesis of 1,3-oxazolidines under thermodynamic control using focused microwave irradiation under solvent-free conditions

A number of 1,3-oxazolidines, derived from enantiomerically pure amino alco hols such as (-)-ephedrine and (+)-pseudoephedrine, have been synthesised u nder solvent-free conditions using a focused microwave reactor. The condens ation reaction between the amino alcohol and an aldehyde yields 1,3-oxazoli dines in excellent yields and diastereoselectivities. Prolonged microwave i rradiation increases the diastereoselectivity of the reaction and produces the thermodynamically more stable diastereomer.