Monoolefin and Diene Cycloaddition Induced by Transition-Metal Carbonyls. Cyclodimerization of 5,6-Dimethylidene-7-oxabicyclo[2.21]hept-2-ene Catalyzed by Dodecacarbonyltriosmium

✍ Scribed by Philippe Vioget; Massimiliano Bonivento; Raymond Roulet; Pirre Vogel

• Publisher: John Wiley and Sons
• Year: 1984
• Tongue: German
• Weight: 604 KB
• Volume: 67
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19840670633

✦ Synopsis

The products generated by heating 5,6-dimethylidene-7-oxabicyclo[2.2.l]hept-2-ene (1) with Fe,(CO),, Ru,(CO),,, Os,(CO),,, Cr(CO),(MeCN),, or W(CO),(MeCN) or by treatment with Fe-atoms have been characterized by spectroscopic methods. Apart from the expected r2and y4-complexes of the triene 1, condensation products are formed which arise from the formal [4 + 21-cyclodimerization of 1 involving the endocyclic double bond of one molecule and the diene moiety of a second. The [4 + 21cyclodimerization is catalyzed by Os,(CO),, in MeOH and gives 1,4-epoxy-7-methoxy-2,3-dimethylidene-l,2,3,4,4a,9,9a, 10-octahydroanthracene (15). Fe-Atoms induce a stereoselective [2 + 21-cyclodimerization of 1 which involves its endocyclic double bond and produces the dimer 8.