Asymmetric α‐Azidation Reaction of β‐Ketoesters Catalyzed by Chiral Tin Alkoxides

Abstract A catalytic enantioselective α‐azidation reaction of β‐ketoesters with an azidated hypervalent iodine reagent was achieved by using an ( R )‐BINOL‐derived chiral tin dibromide possessing 4‐ t ‐butylphenyl groups at the 3‐ and 3’‐positions as the chiral precatalyst in the presence of sodium ethoxide and ethanol. Optically active α‐azido‐β‐ketoesters having a chiral tertiary carbon were obtained in moderate to high yields under the influence of the chiral tin diethoxide generated in situ.