Barton-Zard Pyrrole Synthesis is the process of preparing substituted pyrrole by condensing substituted nitroalkenes with an isocyanoester.
- One alpha hydrogen is removed by the base to form a conjugate base.
- The conjugate base then add with the double bond opposite to the nitro site.
- The negative charge of the carbanion thus produced, combine with the Carbon atom of -CN group.
- After the ring closure, the negatively charged double bond accept proton to become neutral.
- From the other side of the nitrogen, one alpha hydrogen is removed by the base.
- This negative charge now gets delocalised, and ultimately leaves the nitro group from the molecule.
- Finally rearrangement of double bonds occur.