Regiocontrolled synthesis of pyrrole-2-carboxaldehydes and 3-pyrrolin-2-ones from pyrrole Weinreb amides

摘要

A regiocontrolled synthesis of 3,4-disubstituted pyrrole-2carboxaldehydes was completed in two steps from acyclic starting materials. A Barton-Zard pyrrole synthesis between N-methoxy-N-methyl-2-isocyanoacetamide and R-nitroalkenes or,-nitroacetates provided N-methoxy-N-methyl pyrrole-2-carboxamides ( pyrrole Weinreb amides), which were converted into the corresponding pyrrole-2-carboxaldehydes by treatment with lithium aluminum hydride. A regioselective oxidation of the pyrrole-2-carboxaldehydes gave the corresponding 3,4-disubstituted 3-pyrrolin-2-ones.