| Abstract: | Spiro-β-lactams from 2+2]-Cycloaddition of Ketenes to Iminolactones Iminolactones (‘Isoimides’) derived from maleic anhydride and amines are shown to react with various ketenes in a 2+2]-cycloaddition mode. Either preformed ketenes or the combination acid chloride/tertiary amine can be used as reagent. The reaction products have been assigned the spiro-β-lactam structure. Unsubstituted ketene is inert under the reaction conditions. It is possible to synthesize the spiro-β-lactams in a one-pot procedure, starting from a mixture of maleic anhydride/amine and excess dialkylketene. |
