ΔΛ–[Ru(III)(acac)2(dabe)Ru(III)(acac)2], showed that the bridging part became chiral due to the orthogonal twisting of two non-symmetrical β-diketonato moieties. To confirm this conclusion, the complex was resolved chromatographically to provide a pair of opticalantipodes. Such chirality in the bridging part was not generated for [Ru(III)(acac)2(tbet)Ru(III)(acac)2], because the β-diketonato moieties in tbet2− are symmetrical
interpreted by invoking the zwitterion 26 as common intermediate. Monoolefines that cannot generate stable carbenium ions don't give [4+2]cycloadducts with 7a. In contrast, α-methylstyrene yields the oxa Diels–Alder product 30. The structures of (E)-7b, 19, 25, and 27 are established by X-ray diffraction analyses.