Energetically unfavourable Diels-Alder reaction driven by chemical fuel

A petrol pump refilling a fuel tank

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Carbodiimide fuel powers rare, thermodynamically unpromising reaction between diene and dienophile

Chemists have reported a rare instance of a spontaneous, energetically unfavorable reaction powered by a chemical fuel. The team took inspiration from synthetic biology, using a ratchet mechanism to drive the transformation.

For a chemical reaction to be spontaneous, it needs to release energy. This is why spontaneity, in this context, is typically reserved for exergonic reactions – those that release energy on their own. The idea behind a ratchet mechanism is to couple an energy-demanding process with an orthogonal energy input, which provides the energy necessary to satisfy the conservation of energy.