Cyclodimerization of 1-(Dimethoxyniethyl)-5,6-dimethylidene-7-oxa-bicyclo[2.2.1]hept-2-ene Induced by Nonacarbonyldiiron. Crystal Structure of (1RS, 2SR, 3RS, 4RS, 4aRS, 9aSR)- Tricarbonyl[C, 2,3, C-η-(1,4-epoxy-1,5-bis(dimethoxymethyl)-2,3-dimethylidene-1,2,3,4,4a,9,9a,10-octahydroanthracene)]iron

✍ Scribed by Edia Bonlantini; Pierre Vogel; Alan A. Pinkerton

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: German
• Weight: 733 KB
• Volume: 72
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19890720506

✦ Synopsis

The transition-metal-carhonyl-induced cyclodimerization of 5,6-dimethylidene-7-oxabicyclo[2.2.l]hept-2-ene is strongly affected by substitution at C( I). While 5,6-dimethylidene-7-oxahicyclo[2.2.l]hept-2-ene-I-methanol (7) refused to undergo [4 + 21-cyclodimerization in the presence of [Fe2(C0)9] in MeOH, l-(dimethoxymethyl)-5,6-dimethylidene-7-oxabicyclo[2.2.l]hept-2-ene (8) led to the formation of a 1.7:1 mixture of 'trans' (19,21,22) us. 'cis' (20, 23, 24) products of cyclodimerization together with tricarbonyl[C,5,6,C-~-(l-(dimethoxymethyl)-5,6-dimethylidenecyclohexa-1,3-diene)]iron (25) and tricarbonyl[C,3,4,C-q-(methyl 5-(dimethoxymethyl)-3,4-dimethylidenecyclohexa-1,5-diene-l-carboxylate)]iron (26). The structures of products 19 (and of its exo (21) and endo (22) [Fe(CO)3(1,3-diene)] complexes) and 20 (and of its exo (23) and endo (24) [Fe(CO),(1,3-diene)] complexes) were confirmed by X-ray diffraction studies of crystalline (1 RS,2SR,3RS,4RS,4aRS,9aSR)-tricarbonyl[C,2