‘Transformative’ carbonyl cross-metathesis used to synthesise alkenes

Selective cross coupling of carbonyls to form alkenes, especially non-symmetrically, is an important reaction in organic synthesis. However, only a few methods are available and none provide efficient cross-selectivity in carbonyl–alkene reactions. Now, an international team has introduced two strategies for cross-metathesis of carbonyls, enabling carbene-to-ylide transfer and di-metalation to make alkenes.

David Nagib at Ohio State University in the US, who developed the methods with Lumin Zhang from the Shanghai Institute of Organic Chemistry in China, traces the origins of this idea back to 2005, when the chemistry Nobel prize was awarded for the development of metathesis in organic synthesis. ‘I was just a young, naive student,’ Nagib recalls. ‘I thought, “What if you could take two carbonyls and mix them together and make it an alkene in the same process?” And obviously, there are many difficulties for doing it. But it’s been in the back of my mind since 2005.’