140. P. Müller, P. Polleux,
     “Synthesis of a Ketorolac Model via Aromatic Carbenoid Insertion”
     Helv. Chim. Acta 1998, 81, 317-323.

The decomposition of diazo ester 2b with chiral Rh^II catalysts proceeded via intramolecular aromatic carbenoid insertion to the racemic pyrrole derivative 5b in 72% yield. In contrast, the benzoylated precursor 16 afforded no ketorolac 1b when exposed to Rh^II. Methyl 2-diazo-4-phenylbutyrate (19), in turn, reacted, by 1,2-hydrogen migration rather than by aromatic substitution, to 20.

DOI : 10.1002/hlca.19980810212 

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