Organic chemistry: Nickel steps towards selectivity.

Abstract

Hydrocarbons called alkenes are isolated from petroleum as mixtures of isomers, often making it hard to use them as reagents for synthesis. A reaction involving a migrating nickel atom offers a possible solution. See Letter p.84 Functionalizing a specific position on a molecule other than the initial reaction site is a key challenge in synthetic chemistry. Several recent strategies for remote functionalization make use of complex transition-metal complexes to direct bond formation at distant sites. Here, Ruben Martin and colleagues use a cheap and abundant nickel catalyst that adds into a carbon–bromine bond, walks along a hydrocarbon chain and adds carbon dioxide at the terminal position, regardless of where it began. Through a two-step procedure that uses feedstock chemicals, a mixture of saturated hydrocarbons or alkenes can be transformed into a single carboxylic acid product. On carbonyl-containing substrates, the direction of chain migration can be controlled and inverted simply by raising the temperature by 30 degrees Celsius, which switches the reaction from kinetic to thermodynamic control.