Incorporation of two Molecules of Carbon Monoxide into N -Lithioketimine Leading to Azetidine-2,3-Diones

The reaction of N-lithioketimines 1, prepared in situ from R1CN (R1 = t-Bu, 1-adamantyl, CH3OCH2(CH3)2C) and R2Li (R2 = t-Bu, s-Bu), with CO followed by addition of MeI affords azetidine-2,3-diones 2 in 40—86% yields. The reaction involves incorporation of two molecules of CO into the N-lithioketimine.