5-Phenylthio-1,3-oxazinan-4-ones via hetero Diels–Alder reactions: synthesis of (R)- and (S)-Duloxetines and Fluoxetines

The synthesis of 5-phenylthio-1,3-oxazinan-4-ones, through a hetero Diels–Alder strategy, is described. The cycloadducts thus prepared have been shown to be useful intermediates for the synthesis of 1,3-aminoalcohols, valuable intermediates in the preparation of biologically significant molecules, e.g., optically active Duloxetines and Fluoxetines. In the course of this elaboration a novel microwave assisted desulfurization reaction is reported.