Deoxygenation reactions of ortho-nitrostyrenes with carbon monoxide catalysed by metal carbonyls: a new route to indoles

The metal carbonyls Fe(CO)5˙ Ru3(CO)12, and Rh6(CO)16 are catalysts for the deoxygenation of ortho-nitrostyrenes under carbon monoxide pressure to give indole derivatives; the crystal structure of a non-catalytically active rhodium complex obtained during the synthesis of (5e) is reported.