This tutorial review focuses on the rearrangement of b-amino alcohols via aziridinium intermediates. It covers the literature from 1947 to January 2009 (55 references). The rearrangement of b-amino alcohols can be performed by activation of the hydroxy group followed by the addition of nucleophiles (Nu). In most examples, an aziridinium intermediate is involved in the rearrangement. The ratio of amines resulting from the attack of nucleophiles at either the C-1 or C-2 position of the aziridinium intermediate, depends on the nature of the nucleophiles and the R 2 substituent. In some cases, solvent as well as temperature can influence the ratio of amines.Aziridines have been extensively used as useful building blocks. 1,2 The control of the regio-and stereoselectivity in the opening of aziridines provides convenient access to chiral nitrogen-containing compounds. [3][4][5][6] Although N,N-dialkyl aziridiniums are stronger electrophiles than neutral aziridines, their use as key intermediates in organic synthesis is rare. [7][8][9] Aziridiniums, generally obtained through activation of b-amino alcohols, can be opened by a wide range of nucleophiles with or without rearrangement depending on the regioselectivity of the nucleophilic attack.This review covers only the rearrangement of b-amino alcohols of type A, B, and C (Fig. 1) as the rearrangement of prolinols of type D has been recently covered. 10

N,N-Dialkyl-β-amino alcohols were enantiospecifically and regioselectively rearranged by using N,N-diethylaminosulfur trifluoride (DAST) to give optically active β-fluoroamines in excellent yields and enantiomeric excesses. This rearrangement was applied to the enantioselective synthesis of LY503430, a potential therapeutic agent for Parkinson's disease.