Source of materialTo achloroform solution of ethyl 1-cyanocinnamate, two equimolecular amounts of 2-methoxyfuran was added. The resulting solution was stirred for 4days under anitrogen atomosphere. After purification by chromatography, colorless crystals were obtained by slow evaporation from ether/hexane solution at room temperature. DiscussionWe have been studying the Diels-Alder reactions of furans with some electron deficient dienophiles [1,2], and have recently reported that 2-methoxyfuran reacts with 2-nitrostyrenes to give not only the Michael adducts but also the isoxazoline N-oxide [3,4]. Further, reactions using 2-cyanostyrenes as the dienophile give unexpected cyclopropyl derivatives together with the Michael adducts [5,6]. The title compound has the cyclopropyl ring conjugated with the three-electron systems (the vinyl, the phenyl, and the cyano groups) on the same side of the ring plane. The cyclopropyl bond lengths are affected by the interactions with these groups. The proximate bonds (d(C1-C2) =1 .528(4) Å and d(C1-C3) = 1.556(4) Å)ofthe cyclopropane ring bearing the phenyl group are significantly elongated by 0.04 Å (mean values) compared to the distal bond (d(C2-C3) =1.491(4) Å)which has the normal bond length (1.497 Å) [7]. The difference between the proximal bond lengths C1-C2 and C1-C3 demonstrate not only the difference between the electronic effect of the vinyl group and the phenyl group with its synchronous orientation, but also the steric clash between the cyano group and these groups. The angle at the point of the cyano group is smaller than the other two angles (∠C2− C1−C3 =57.8(2)°vs. ∠C1−C3−C2 =60.2(2)°and ∠C1−C2−C3 =62.0(2)°).