You are currently viewing the abstract.
View Full TextLog in to view the full text
AAAS login provides access to Science for AAAS members, and access to other journals in the Science family to users who have purchased individual subscriptions.
Register for free to read this article
As a service to the community, this article is available for free. Existing users log in.
More options
Download and print this article for your personal scholarly, research, and educational use.
Buy a single issue of Science for just $15 USD.
Carbon-carbon bonds without byproducts
Environmental and cost concerns are spurring development of chemical methods that minimize byproduct formation. In this vein, Mo and Dong present a catalyst that inserts olefins such as ethylene directly into the C-H bonds of ketones. Traditional methods to form such products rely on the preliminary reaction of the ketone with a base, followed by subsequent reaction with an alkyl halide. The authors used a ligand that simultaneously activates the ketone and guides the catalytic rhodium to the right location. This approach removes the need for the other reagents and eliminates the associated halide salt byproducts.
Science, this issue p. 68
Abstract
Alkylation of carbonyl compounds is a commonly used carbon-carbon bond–forming reaction. However, the conventional enolate alkylation approach remains problematic due to lack of regioselectivity, risk of overalkylation, and the need for strongly basic conditions and expensive alkyl halide reagents. Here, we describe development of a ketone-alkylation strategy using simple olefins as the alkylating agents. This strategy employs a bifunctional catalyst comprising a secondary amine and a low-valent rhodium complex capable of activating ketones and olefins simultaneously. Both cyclic and acyclic ketones can be mono-α-alkylated with simple terminal olefins, such as ethylene, propylene, 1-hexene, and styrene, selectively at the less hindered site; a large number of functional groups are tolerated. The pH/redox neutral and byproduct-free nature of this dual-activation approach shows promise for large-scale syntheses.
