The use of N-boc-1,3-oxazolidines as chiral auxiliaries in asymmetric synthesis

This microreview presents the use of 1,3-oxazolidines, prepared from enantiomerically pure beta-amino alcohols, as chiral inductors for the stereoselective transformation of adjacent prostereogenic C=C or C=O bonds. After a brief chronological presentation of the major advances in this field, a convenient synthesis of N-Boc-2-acyl- and -2-alkenyloxazolidines is presented, together with the use of these heterocycles in asymmetric synthesis. The important role played by the Boc group on the nitrogen of the heterocycle in these trans-formations is emphasized. In addition to its well known properties as a protecting group, this carbamate actively contributes to the efficiency of this chemistry. Thanks to its bulkiness and chelating properties, it contributes to an efficient stereodifferentiation of the close prostereogenic moiety, but can also directly react with this moiety either as an electrophile or as a nucleophile. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.