Synthesis and acid- and base-promoted ring opening of polycarbocyclic oxiranes

✍ Scribed by Alan P Marchand; Eric Zhiming Dong; Simon G Bott

• Publisher: Elsevier Science
• Year: 1998
• Tongue: French
• Weight: 784 KB
• Volume: 54
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(98)00162-8

✦ Synopsis

Acid promoted ring opening of la,4a,4act,9aa-tetrahydro-21B-31B-elx3xy-1,4-methanoanthracene-9,10-dione and the corresponding 2-methyl de,'ivative (i.e., 3a and 3b, respectively) afforded 4a and 4b in 26% and 49% yield, respectively. Similar results were obtained when a solution of either 3a or 3b in aqueous acetone was reacted with Na2CO3 at ambient temperature for 2 days. However, reaction of 3b with aqueous methanolic NaOH (ambient temperature, 7 days) produced a small quantity of 4b along with a novel pentacyclic diketone, 6b (44% yield). Finally, acid promoted ring opening of la,4a-dihydro-4act,9act-epoxy-l,4-methanoanthracene-9,10-dione (12) resulted in extensive skeltal rearrangement of the substrate, thereby affording 14 in low yield.