Novel Synthesis of Aryl Cyclopropylketones

Alexandre Gagnon presents the cross-coupling between aryl(heteroaryl) iodides and tricyclopropylbismuth.

Palladium-Catalyzed Carbonylative Cross-Coupling Reaction between Aryl(Heteroaryl) Iodides and Tricyclopropylbismuth: Expedient Access to Aryl Cyclopropylketones: E. Benoit, J. Dansereau, A. Gagnon Synlett 2017, DOI: 10.1055/s-0036-1590832

The cyclopropyl group is a privileged fragment in drug discovery, as demonstrated by the fact that a number of bioactive compounds incorporate a cyclopropyl ring. A useful class of building blocks for the introduction of this unit into an organic compound are aryl cyclopropyl ketones, which are generally obtained by Friedel–Crafts acylation of electron-rich aromatics with cyclopropanoyl chloride. This reaction has its limitations of scope since aromatic substrates incorporating electron-poor rings or sensitive functions cannot be easily prepared by this route. Recently, the group of Professor Alexandre Gagnon from the Université du Québec à Montréal (Canada) reported a new convenient method for accessing the title compounds.

Professor Gagnon said: “Our team at UQAM found that (SIPr)Pd(allyl)Cl, an N-heterocyclic carbene palladium(II) catalyst, promotes the carbonylative cross-coupling reaction between aryl iodides and tricyclopropylbismuth under 1 atmosphere of carbon monoxide and in the presence of lithium chloride, to afford aryl cyclopropylketones, which are useful synthons in organic chemistry.”