Straightforward Synthesis Of Succinimide-Fused Pyrrolizidines By A Three-Component Reaction Of Alpha-Diketone, Amino Acid, And Maleimide

An efficient, one-pot, three-component [3+2] cycloaddition reaction of azomethine ylide obtained from alpha-dicarbonyl compounds (cyclic and acyclic diketone or keto ester) and amino acids with maleimides under catalyst-free conditions has been developed. This cascade protocol shows high efficiency and remarkable functional group tolerance, and the ubiquitous succinimide-fused pyrrolizidines with a highly compact and strained scaffold were obtained with high yield and excellent diastereoselectivity. Furthermore, this novel and atom-economical strategy could be performed on a gram scale with comparable reaction efficiency.