LAUSR

The Baldwin rearrangement is a thermally induced ring contraction of 4-isoxazolines into 2-acylaziridines. The reaction yields highly strained nitrogen-containing three-membered-ring compounds from readily available five-membered N-O heterocycles. Diversely substituted isoxazolines are directly transformed into a variety of highly functionalized 2-acylaziridines in a stereocontrolled process. In this review mechanistic aspects and stereoselectivity of this rearrangement are discussed. Although still undervalued, the Baldwin rearrangement may have significant applications in the synthesis of complex aziridine-containing targets such as natural products or pharmaceuticals.