Preparation and supporting on solid phase of chiral auxiliary (S)-4-(4hydroxybenzyl)oxazolidin-2-one from L-tyrosinol assisted by Microwaves

Abstract

An oxazolidinone chiral auxiliary, (S)-(4-Hydroxybenzyl)1,3-oxazolidin-2-one 4 was prepared in 23-80 % yield from L-tyrosinol using different methodologies. In solution, compound 4 was protected with a benzyl group on the phenolic hydroxyl 5a, which allowed the optimization of the solid phase synthesis of 5b-5d. Chiral auxiliaries 5a and 5b reacted in solution with an α,β-unsaturated system to give (S)-4-(4-(benzyloxy)benzyl)-1,3-oxazolidin-2-one 6a. By contrast, in solid phase the same reaction afforded 6b. Both reactions were carried out under microwave activation. New compounds were characterized by 1H and 13C NMR, infrared spectroscopy and mass spectrometry.