Condensation of 2,3-Di(Methylidene)-7-Oxabicyclo[2.2.1]Heptane Derivatives into Dicarbonyl[Eta-3-Eta-3-Octa-2,6-Diene-1,8-Diyl]Iron Complexes with Nonacarbonyldiiron - Crystal-Structure of (1rs,2rs,3rs,4sr,5rs,6sr,1'rs,2'rs,3'rs,4'sr,5'rs,6'sr)-Dicarbonyl-((2,3 ,C-Eta-2',3',C-Eta)-2,2'-Ethylene-5,5',6,6'-Tetrakis[(Methanesulfonyloxy )-Methyl]-3,3'-Di(Methylidene)-Bis[7-Oxabicyclo[2.2.1]Hept-2-Yl)Iron

The reactions of [Fe2(CO)9] with 2-exo,3-exo-bis(chloromethyl)-5,6-di(methylidene)-7-oxabicyclo[2.2.1]hep tane (5) and with 5,6-di(methylidene)-7-oxabicyclo[2.2.1]heptane-2-exo,3-exo-dimethyl bis(methanesulfonate) (6) afforded, together with the corresponding [exo-Fe(CO)3(1,3-diene)] complexes 7 and 8, the products of dimerization in the form of stable [Fe(CO)2{1,2,3-eta:6,7,8-eta)-octa-2,6-diene-1,8-diyl}] complexes 9 and 10, respectively, with high stereoselectivity. The structure of 10 was established by means of single-crystal X-ray diffraction.