Total Synthesis of the Novel Coenzyme Methoxatin

A convergent total synthesis of the novel coenzyme methoxatin is described. This coenzyme is a pyrroloquinoline quinone tailored for efficient oxidation of methanol and formaldehyde in methylotrophic bacteria. The synthesis was achieved by joining a pyrrole subunit with uvitonic acid ester followed by photocyclization of the resulting olefin to deoxymethoxatin 10. Conversion of 10 to methoxatin proceeded in five steps and led to some elaboration of the chemistry of the unusual pyrroloquinoline heterocycle. The overall yield is ~15% in 11 operations