A Concise and Efficient Synthesis of Substituted Morpholines

A simple and efficient method has been developed for the synthesis of substituted morpholines by a sequence of coupling, cyclization, and reduction reactions of easily available amino alcohols and α-halo acid chlorides. Various mono-, di-, and trisubstituted morpholines, spiro morpholines, and ring-fused morpholines, as well as morpholine homologues, were synthesized in good to excellent yields by a single methodology under similar reaction conditions. The method was also used in a multigram synthesis of (3S)-3-methylmorpholine.