Rh(II)-Catalyzed Monocyclopropanation of Pyrroles and Its Application to the Synthesis Pharmaceutically Relevant Compounds.

Here we report Rh(II)-catalyzed monocyclopropanation reactions on pyrroles in the presence of aryldiazoacetates, providing the corresponding dearomatized products with high levels of enantioselectivity (up to >99% ee). Under the catalysis of Rh2(R-p-PhTPCP)4, a broad range of pyrrole substrates and aryldiazoacetates are shown to be compatible. Utilizing these valuable chiral building blocks, we further demonstrate the application of this transformation by synthesizing a homo-β-proline analog and a β-aminocarboxylic acid (β-ACC) derivative from the monocyclopropanated product.