Multicomponent Synthesis of Pyrroles from Cyclopropanes: A One‐Pot Palladium(0)‐Catalyzed Dehydrocarbonylation/Dehydration

Ring the changes : The cycloaddition of nitrones with 1‐carboallyloxy‐1‐carbomethoxycyclopropanes yields tetrahydro‐1,2‐oxazines, which in turn undergo a Tsuji dehydrocarbonylation to give dihydro‐1,2‐oxazines (see scheme; dba=dibenzylideneacetone). Addition of base to this reaction mixture results in clean conversion to pyrroles. The result is a flexible three‐component strategy for the synthesis of tetrasubstituted pyrroles.