An Efficient Synthesis of (4S)-(-)-4-Isopropyl-2-oxazolidinone

Article abstract of DOI:10.1055/s-1989-27337

A new, efficient, cost-effective method for the preparation of the Evans'chiral auxiliary (4S)-4-isopropyl-2-oxazolidinone (4) is described.A Schotten-Baumann acylation of valine with phenyl carbonochloridate quantitatively affords the protected valine, which is then reduced with borane in tetrahydrofuran to give an alcohol.Cyclization with a catalytic amount of potassium tert-butoxide gives 4 in 81percent overall yield and in 41-43percent after crystallization from ethyl acetate/n-hexane.