Researchers at the University of Santiago de Compostela report a light-driven method that directly “allylates” methane—adding an allyl group that can be used to build more complex molecules—and they demonstrate the approach by producing the nonsteroidal estrogen dimestrol from methane.
Natural gas is a widely used energy resource and is composed mainly of methane, along with other light alkanes such as ethane and propane. Much of it is burned for heat and electricity, which releases greenhouse gases.
A research team led by Martín Fañanás at the Centre for Research in Biological Chemistry and Molecular Materials (CiQUS) at the University of Santiago de Compostela has reported a new way to convert methane and other gaseous alkanes into more useful chemical intermediates. The work was published in Science Advances.
Turning methane into a reactive “handle”
The researchers centered their approach on C–H allylation, a reaction that attaches an allyl group to an alkane. By adding this functional “handle,” the resulting product can serve as a starting point for further synthesis into higher-value chemicals.
In a demonstration of synthetic utility, the team reports a “telescoped” route in which methane is converted into more complex compounds, including dimestrol, which the researchers describe as a nonsteroidal estrogen used in hormone therapy.
Controlling side reactions with a supramolecular iron catalyst
A key problem for methane functionalization in this type of chemistry is avoiding competing reactions that consume the starting material and generate unwanted byproducts. The CiQUS team says their system was prone to alkane C–H chlorination as a side reaction.
To address this, they designed a supramolecular photocatalytic system based on an in situ formed tetrachloroferrate species stabilized by collidinium (protonated collidine). “The core of this breakthrough lies in designing a catalyst based on a tetrachloroferrate anion stabilized by collidinium cations, which effectively modulates the reactivity of the radical species generated in the reaction medium,” Fañanás said in the CiQUS statement carried by ScienceDaily.
According to the report, a hydrogen-bonding network around the iron complex helps preserve the desired photocatalytic reactivity while suppressing competing chlorination pathways, improving selectivity for allylation.
Light-driven conditions and broader context
The method uses an iron-based photocatalyst and LED light. The researchers and CiQUS describe the approach as operating under relatively mild temperatures and pressures compared with many traditional methane-activation routes.
CiQUS said the work forms part of a broader research effort supported by the European Research Council aimed at upgrading natural-gas components into higher-value chemicals. The center also notes that it holds the CIGUS accreditation from the Galician government and receives funding linked to the Galicia FEDER 2021–2027 program.
