Highly Enantioselective Access to α‐Dibenzylamino Ketones from Chiral Nonracemic α‐Bromo α′‐Sulfinyl Ketones by Dynamic Kinetic Resolution: Synthesis of (2R,1′S)‐2‐[1‐(Dibenzylamino)alkyl]oxiranes
A novel and efficient synthesis of enantiomerically pure alpha-dibenzylamino alpha'-sulfinyl ketones starting from a mixture of both epimers of alpha-bromo alpha'-(R)-sulfinyl Ketone has been realized through combined in situ substitution-epimerization in so-called Dynamic Kinetic Resolution (DKR). The scope of the reaction has been examined, and four differently substituted alpha-(S)-dibenzylamino alpha'-(R)-sulfinyl ketones were obtained in good yields with excellent diastereoselectivities. The utility of these derivatives was further illustrated with a highly stereoselective synthesis of syn-(2R, 1'S)-2-(1-dibenzylaminoalkyl)oxiranes.