Two-carbon ring expansion of cyclobutanone skeletons by nickel-catalyzed intermolecular alkyne insertion

The reaction of cyclobutanone with an alkyne in the presence of a nickel(0) catalyst formally achieves intermolecular alkyne insertion between the carbonyl carbon and the a-carbon of a cyclobutanone, providing a six-membered carbocyclic skeleton. (c) 2006 Elsevier Ltd. All rights reserved.