Ru(0)-Catalyzed C3-Selective Cross-Dimerization of 2,5-Dihydrofuran with Conjugated Dienes

Cross-dimerization of 2,5-dihydrofuran with conjugated dienes enables a straightforward and efficient synthesis of C3-substituted 2,3-dihydrofurans. The reaction has been achieved by Ru­(η⁶-naphthalene)­(η⁴-1,5-COD) (1) (3–10 mol %) in acetone at room temperature. This protocol is also effective for branched and linear internal conjugated dienes. The stereochemistry of the products suggests that the reaction involves the oxidative coupling step between cisoid-1,3-dienes and 2,5-dihydrofuran at a Ru(0) center.