The Pd-mediated reduction of o-nitrostilbenes in the presence of carbon monoxide is reported to proceed regioselectively under pressurised flow-through conditions to cleanly afford indoles.

A variety of substrates are tolerated and the reaction proceeds significantly faster  than in batch and produces carbon dioxide as the only stoichiometric side-product.

Publication 61Continuous Flow Synthesis of Indoles by Pd-Mediated Reduction of o-Nitrostilbenes with Carbon Monoxide.pdf