Synthesis of Spiro{pyrrolidine-3,1′-pyrrolo[3,4-c]pyrrole} Basic Framework by Multicomponent 1,3-Dipolar Cycloaddition

The synthesis of the complex spiro{pyrrolidine-3,1 '-pyrrolo[3,4-c]pyrrole} skeleton under mild conditions is presented. The order of addition of a primary amine, two equivalents of the corresponding maleimide and, finally, the aldehyde is of a paramount importance to obtain these final compounds in very high yields. The mechanism was studied by performing very simple tests, the Michael type addition of the amine onto the maleimide being the key step. Interestingly, the hybrid scaffold was prepared by sequential addition of two different maleimides. In addition, a more interesting architecture was prepared through a metathesis reaction between allylic residues bonded in the molecule precursor.

Automated summary

The synthesis of complex spiro{pyrrolidine-3,1'-pyrrolo[3,4-c]pyrrole} skeleton under mild conditions is presented, with the order of addition of a primary amine and two equivalents of corresponding maleimide being crucial for high yields. The mechanism was studied by simple tests, revealing the Michael type addition of the amine onto the maleimide as a key step. Interesting scaffold hybrids were prepared through sequential addition of two different maleimides, and a more intriguing architecture was obtained through a metathesis reaction between allylic residues in the molecule precursor.