Abstract: | Structure and Partial Synthesis of Dimeric Coleon F Coleon F ( 1a ), on standing in solution, slowly dimerizes to the labile C(7)-epimeric spiro-dihydrofuranes 2a/2b whose structures were elucidated by spectroscopic methods. Oxydative addition of 1a to another molecule of 1a in the presence of Fétizon's reagent rapidly yields 2a/2b , thus confirming their structures as (4bS,9RS,10′aS)4,4a,10′,10′a-tetrahydro-1′,6-dihydroxy-1,2,4a,7′,8′,10′a-hexamethyl-3′,7-bis(2-propenyl)-spiro3H,9H-phenanthren-9,5′-5′H-phenanthro1,10-bc]furan]-2,3,5,8,9′-pentone. |